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Intel Core i7-2600K and i5-2500K Processors Debut
Date: Jan 02, 2011
Author: Marco Chiappetta
Introduction and Specifications

Today’s pre-launch of Intel’s Sandy Bridge-based processors should come as no surprise to anyone who even remotely follows the PC tech scene. We, along with Intel and numerous other companies and media outlets, have been slowly leaking Sandy Bridge and Sandy Bridge-related details for many months now. Heck, we’ve even showed off a number of Sandy Bridge compatible motherboards in the past, posted pics of actual processors, and discussed many of the microarchitecture’s features already. We obviously weren’t able to disclose all of the platform’s specifics, however, and boy is there a lot still to cover. That’s what this article is for.

We’ve had a few Core i5 and Core i7 Sandy Bridge based processors kicking around the HotHardware labs for a while now, along with a sampling of 6-series chipset based motherboards to go along with them. We’ve been poking, prodding, and testing them to get a good feel for what Sandy Bridge and 6-Series chipset is all about and we’ve amassed a boatload of data to share with you all here. In addition to putting a couple of Core i5 and Core i7 Sandy Bridge based processors to the test in our usual suite of benchmarks, we’ve also tested their new integrated graphics core and media encoding engine, tested various multi-GPU setups, overclocked Sandy Bridge, and even evaluated a few mainstream and enthusiast-class motherboards.

Our aim was to provide a sort of “one stop shop” for all things Sandy Bridge. Whether we’ve succeeded or not doesn’t really matter, because there’s a ton of info and data to work through regardless! And when you're done here, we've also got the down low on Sandy Bridge mobile offerings as well. So step right up, get your mice warmed up, and strap in as we (finally) give you the full scoop on Sandy Bridge and all of the goodness that’s coming along with it...

Intel Socket 1155 Sandy-Bridge Based Core i5 Processor, Click To Enlarge

Intel Core i7-2600K and i5-2500K Processors "Sandy Bridge"
Specifications & Features

Intel Core i7-2600K Processor Key Features:

  • 8-Way Multi-Task Processing: Runs 8 independent processing threads in one physical package.
  • Intel Turbo Boost Technology 2.0: Dynamically increases the processor frequency up to 3.80GHz when applications demand more performance. Speed when you need it, energy efficiency when you don’t.
  • Intel Hyper-Threading Technology: Allows each core of the processor to work on two tasks at the same time providing unprecedented processing capability for better multi-tasking, and for threaded applications.
  • Intel Smart Cache: 8MB of shared cached allows faster access to your data by enabling dynamic and efficient allocation of the cache to match the needs of each core significantly reducing latency to frequently used data and improving performance.
  • Intel HD Graphics 3000: Significant 3D performance for immersive mainstream gaming on a broad range of titles. The dynamic graphics frequency ranges up to 1350MHz.

Intel Core i5-2500K Processor Key Features:

  • 4-Way Multi-Task Processing: Runs 4 independent processor threads in one physical package.
  • Intel Turbo Boost Technology 2.0: Dynamically increases the processor frequency up to 3.7 GHz when applications demand more performance. Speed when you need it, energy efficiency when you don’t.
  • Intel Smart Cache: 6MB of shared cached allows faster access to your data by enabling dynamic and efficient allocation of the cache to match the needs of each core significantly reducing latency to frequently used data and improving performance.
  • Intel HD Graphics 3000: Significant 3D performance for immersive mainstream gaming on a broad range of titles. The dynamic graphics frequency ranges up to 1100MHz.

Shared Features:

  • CPU Overclocking Enabled (with Intel P67 Express Chipset): Fully unlocked core multiplier, power, and DDR3 memory ratios enable ultimate flexibility for overclocking.
  • Graphics Overclocking Enabled (with Intel H67 Express Chipset): Unlocked graphics multiplier allows for overclocking to boost the graphics clock speed.
  • Integrated Memory Controller: Supports 2 channels of DDR3-1333 memory with 2 DIMMs per channel. Support for memory based on the Intel Extreme Memory Profile (Intel XMP) specification.
  • Chipset/Motherboard Compatibility: Compatible with all Intel 6 Series Chipsets.
  • AES-NI: Provides 6 processor instructions that help to improve performance for AES encryption and decryption algorithms.
  • Built-in Visuals3: New enhanced built-in visual features deliver a seamless visual PC experience for doing everything from simple e-mail to enjoying the latest 3D and HD entertainment. The built-in visuals suite includes:
  • Intel Quick Sync Video Technology: Media processing for incredibly fast conversion of video files for portable media players or online sharing.
  • IntelInTru3D: Stereoscopic 3D Blu-ray* playback experience in full HD 1080p resolution over HDMI 1.4 with 3D.
  • Intel Clear Video HD Technology: Visual quality and color fidelity enhancements for spectacular HD playback and immersive web browsing.
  • Intel Advanced Vector Extensions (Intel AVX): Increased performance for demanding visual applications like professional video & image editing.

Intel Sandy Bridge Processor Die

For those of you not quite familiar with Intel’s codenames, Sandy Bridge is the codename of a brand new microarchitecture that will be foundation of an entire line of desktop and mobile processors in 2011 and beyond. It is a “Tock” in Intel’s CPU release cadence, which means it is almost completely new and not a mild revision of an existing microarchitecture.

Above we have a die shot of a Sandy Bridge processor, along with the features and specifications of the new Core i5-2500K and Core i7-2600K processors we’ll be showcasing here. Some of the features will sound similar to previous Intel processor offerings, but make no mistake, these are completely new chips. They may borrow some aspects from previous Intel CPU microarchitectures, but with Sandy Bridge, Intel has redesigned virtually all of the execution engines, integrated a relatively powerful graphics core, and implemented a new ring bus to allow core elements to communicate, among many other features and enhancements.

Sandy Bridge Microarchitecture

As we’ve mentioned, the Sandy Bridge microarchitecture is almost completely new. The out of order execution engines and the Floating Point units in Sandy Bridge were re-designed from the ground up in an effort to further optimize for power efficiency and performance over previous Intel processor designs.

In the OOO engines, Intel went to a physical register file. This reduces die area and can also lower power because it eliminates duplicated data in various registers and minimizes the amount of of data movement around the chip. This, and other techniques used in the OOO engines allowed Intel to incorporate larger OOO buffers, which also provide a bigger window to find Instruction Level Parallelism (ILP), which can increase performance on legacy code. The reduction in register space and data movement is also essential for AVX (Advanced Vector Extensions), where data vectors are 2x the size of previous generations. AVX is a new set of instructions in Sandy Bridge that improves Floating Point and Vector computation performance.

The brand prediction units in Sandy Bridge were also completely redesigned. Intel’s branch predictors in Nehalem were already very efficient, but changes were made to the branch predictors in Sandy Bridge to provide more accuracy through more branch targets, more branch history and other mechanisms, while keeping similar die area to Nehalem. According to Intel, the changed here included “better representation of the additional information (such as longer history) in the same or similar amounts of bits. For example, split targets into close ones (that require less address bits for knowing the distance) and far ones (that require all the address bits). Similarly for history – find out what history can be reduced, and use the freed-up bits for the branches that require more history.”

Sandy Bridge is also outfitted with new micro-op cache. The decoded micro-OP cache provides high and consistent bandwidth, at much lower latency, than the traditional front end decode path. It also provides the UOPs at much lower power than the traditional front end.

The cache structure in SB is somewhat of a departure from previous designs as well. There are specific amounts of L1 and L2 cache per CPU core and a larger Last Level Cache that both the CPU and graphics cores can share. The LLC helps both 3D graphics and Media (video) by providing very high bandwidth, low latency and low power data repository. Intel also built in a fine grained shared cache control at the per data stream (or data buffer) level for the graphics core that allows us to fine tune the cache sharing. For example, for H.264 video decoding, Intel was able to cut down the DRAM bandwidth by roughly 50% by mapping small scratch buffers to the last level cache while allowing other large video buffers to bypass the LLC.

Another new feature of Sandy Bridge is a high-bandwidth, low-latency ring bus that links all of the core elements in the processor. The system agent, CPU execution cores, graphics core, and last level cache are all linked on the ring bus, which is used to quickly route date to and from these core processor elements.

Making a return on Sandy Bridge is Intel’s Turbo Boost technology, but it too has been revamped. In addition to allowing the CPU cores to be dynamically overclocked, Turbo can also boost the frequency of Sandy Bridge’s integrated graphics core as well. In addition, the new Turbo Boost implementation will also allow Sandy Bridge processors to run beyond their rated TDP in short spurts to further increase performance.


Vital Signs and Overclocking

Below are a couple of screenshots from the latest version of CPU-Z that detail some of the new Core i5-2500K and Core i7-2600K processors’ inner-workings.

Core i5-2500K CPU Details

Core i5-2500K Cache Details

Core i7-2600K CPU Details

Core i7-2600K Cache Details

As you can see, and we’ve already mentioned, the chips utilize the new socket 1155 and are built using Intel’s 32nm process node. The chips we tested and that will hit retail shelves are revision D2, with stepping 7 and they feature a 100MHz BCLK. And other than their frequencies, support for HyperThreading and L3 / LLC cache sizes, the Core i5-2500K and Core i7-2600K are essentially identical.

The Core i5-2500K has 6MB of L3, whereas the i7-2600K has 8MB. There is 64K (32K data, 32K instruction) of L1 cache per core, and 256K of L2 cache per core. All of the caches are 8-way set associative, with the exception of the L3 / LLC which is 12-way set associative on the Core i5-2500K and 16-way on the i7-2600K.

There has been a lot of scuttlebutt regarding Sandy Bridge and its potentially limited overclocking. The reason for all the chatter is because Sandy Bridge based processors have an on-die clock generator and much more complex design that cannot handle high BCLK frequencies in its current form. So, what Intel has done in an attempt to satisfy the overclocking market is introduce K-series SKUs that are totally unlocked for easy overclocking via multiplier manipulation. But take note that other non-K SKUs will also have “limited” unlocking which will allow for multipliers to be increased by up to 4 speed bins above the processor’s peak, official Turbo frequency. Now, while there’s not nearly as much BCLK headroom as previous architectures, that doesn’t mean it can’t be altered at all. The BCLK on current Sandy Bridge chips can typically be increased by up to 5%-9% or so. With a default BCLK of 100MHz, that means about 105MHz to 109MHz (give or take a few MHz) will typically be possible, depending on the particular chip.

The highest multiplier available on K SKUs is 57, which would equate to 5.7GHz, but it’s not likely that kind of frequency will be possible. These processors are highly overclockable, though.

Intel Core i7-2600K Overclocked to 4.57GHz

We spent some time tweaking our Core i7-2600K using the stock Intel high-performance cooler and an Asus P8P67 Deluxe motherboard and were easily able to hit a rock-solid and perfectly stable peak frequency of 4.57GHz. We achieved this speed by increasing the CPU voltage to 1.35v, with a multiplier of 44 and a BCLK of 104MHz. With more tweaking, we're certain higher clocks will be possible. We were actually told by Asus that approximately 50% of Sandy Bridge CPUs can hit 4.4-4.5GHz, 40% can hit up to 4.6-4.7GHz, and about 10% will reach up to 4.8-5GHz. We should also mentioned that at the speeds we hit, with the stock cooler, temperatures were absolutely not an issue. While overclocked, the 2600K idled in the high 40'C range and peaked in the low 70'C range.


HD Graphics and Media Encoding


One of the stand-out features of Intel’s new Sandy Bridge processors is its integrated DX10.1 graphics core. The graphics core that incorporated into Sandy Bridge is a significant step up from any other graphics product Intel has every introduced. With that said, it is not a replacement for a mid-range or high-end discrete graphics card, but it does offer feature and enough performance to satisfy a significant portion of the market.

Sandy Bridge based Intel Core i5 and Core i7 processor will feature one of two graphics core configurations, Intel HD Graphics 2000 or Intel HD Graphics 3000. The two differ only in their number of execution units, or cores. Intel HD Graphics will have 6 EUs enabled, while HD 3000 Graphics will have 12. The graphics cores on the different processors will also differ in their peak frequencies as well. For example, the Core i5-2500K has a peak graphics core frequency of 1100MHz, while the Core i7-2600K’s graphics core can hit up to 1350MHz.

All Sandy Bridge based K SKUs will feature the Intel HD Graphics 3000 core. Non-K SKUs will feature Intel HD Graphics 2000. If you ask us, this is somewhat backwards. K SKU buyers are more likely to use a discrete GPU, than standard CPU buyers. You’d think it would be more beneficial if the standard CPUs got the faster graphics configuration, because it’s more likely to get used by the consumers who’d buy those chips.

Features of the new Intel graphics core include stereoscopic 3D support, dubbed InTru 3D, Clear Video HD for image quality enhancement, WiDi (Wireless Display), and an integrated media processing engine for hardware accelerated Encoding, Decoding and Transcoding. Intel is calling the media processing engine Quick Sync Video.

Quick Sync work much like the GPU accelerated Encoding, Decoding and Transcoding we’ve seen from NVIDIA and AMD and offers vastly increased performance over software-based solutions. Like NVIDIA’s and AMD’s offerings, software vendors will have to specifically code for Intel QuickSync technology, but that should be happening fairly quickly. We have already worked with pre-release packages from Corel, CyberLink and ArcSoft that can take advantage of Quick Sync.

As you’ll see later, we found Intel’s Quick Sync technology to offer exceptional performance, but there is a significant caveat, at least with desktop processors. Users must be utilizing the processor’s integrated graphics core to take advantage of Quick Sync. If a discrete graphics card is installed in the system and a single montior is attached to it, the desktop processor’s integrated Intel HD Graphics 2000/3000 series graphics core is disabled, with Quick Sync along with it. To use Quick Sync along with a discrete GPU, monitors will have to be attached to both the GPU and Intel integrated graphics.


6-Series Chipsets, Intel Motherboards


To accompany the new Sandy Bridge Core i5 and i7 based processors, Intel is also introducing a whole family of chipsets—the 6-series.

Intel P67 Chipset Diagram

Above is a high-level block diagram of the flagship P67 chipset which is targeted at the performance and enthusiast segments, but there will be a number of other 6-series chipsets arriving as well, that target SMB and consumer segments. There will be mobile variants of each introduced coming down the pipeline too.

The P67 chipset is essentially an I/O hub, as all of the traditional Northbridge functionality has been integrated into the processor itself. As you can see, Sandy Bridge processors offer 16 lanes of PCI Express 2.0 connectivity and they feature integrated dual-channel, DDR3 memory controllers. The processors are linked to the chipset via a 20Gb/s interface and the P67 itself it outfitted with 8 more PCIe 2.0 lanes, along with various other I/O, like USB 2.0, SATA, etc. The 6-series chipsets have native support for SATA 6Gbs, but not USB 3.0. USB is only available through the use of a third-party controller.

The various 6-series desktop chipsets are listed above. They chipsets differ mainly in the number of USB and SATA 6Gps ports are supported, and in their support performance tuning, content protection, and RST 10 modes, but they are fundamentally very similar and all are actually based on the same die. Also note that the P67 does not support integrated display outputs, so Sandy Bridge’s integrated processor graphics is not available with the P67.


DH67BL (Bearup Lake - Left) and DP67BG (Burrage - Right)

We got our hands on a couple of Intel-built motherboards to test the new Sandy Bridge-based processors, the DH67BL (Bearup Lake) and DP67BG (Burrage). The DH67BL is a micro-ATX motherboard based on the H67 chipset, with full integrated display support. And the DP67GB is an enthusiast-class P67-based motherboard, sans display outputs. Both of the boards exploit all of the features inherent in the H67 and P67 chipsets and also feature NEC USB 3.0 controllers.

For all of our graphics-related Sandy Bridge testing, the DH67BL was used. And we’ve got a full run of numbers utilizing the DP67BG as well, along with a few more using motherboards from Asus, MSI, and Gigabyte.


P67 Motherboards: Asus, MSI, Gigabyte


For the purposes of this article, in addition to the Intel-built boards on the previous page, we acquired a handful of enthusiast-class P67-based motherboards to give you all an idea as to what type of boards would be hitting the scene along with the new Sandy Bridge-based Core i5 and i7 based processors.

Asus P8P67 Deluxe Motherboard, Click To Enlarge

First up, we have the Asus P8P67 Deluxe. The P8P67 Deluxe is about as feature rich a motherboard as we have come across. In addition to exploiting all of the features inherent to the P67 chipset, the P8P67 Deluxe offers USB 3.0 support (with front panel USB 3.0 ports included), Bluetooth connectivity, additional SATA 6Gbps ports, and what Asus is calling “Dual Intelligent Processors 2”. The Dual Intelligent Processors consist of Asus’ EPU unit, which we’ve covered in the past, and the TurboV processing unit. The processors work together with the P8P67 Deluxe’s 16+2 digital VRM (DIGI+ VRM) and give users the ability to monitor and adjust power delivery. According to Asus, the combination of the programmable digital VRM and DIP2 results in superior efficiency and longevity.

The Asus P8P67 Deluxe also supports SLI and CrossFireX, DTS Surround, and Asus includes a copy of their AI Suite II, which gives users easy access to all of the Asus-proprietary features mentioned here in a single software package. In addition to the aforementioned features, the P8P67 Deluxe also sports an EFI BIOS that’s worlds better than traditional text-based BIOS menus. Take a look.

We found the Asus P8P67 Deluxe to be a very stable board that was quite tweaker-friendly too. Performance was also excellent, as you’ll see in the pages ahead.

MSI P67A-GD65 Motherboard, Click To Enlarge

Here we have the MSI P67A-GD65. Like the other P67-based motherboards featured here, all of the P67 chipset’s features are available on the P67A-GD65, but MSI works a bit of their magic as well. The MSI P67A-GD65 features a mouse-friendly EFI BIOS that’s much easier to navigate than traditional text-based BIOS menus. The board is also in MSI’s “Military Class II” family and features super ferrite chokes, highly conductive polymer capacitors, and solid capacitors throughout, which should offer increases stability and longevity.

The MSI P67A-GD65 also supports “1 second overclocking” thanks to its OC Genie feature, but the BIOS also sports all of the overclocker-friendly features we’ve come to expect from MSI for manual tweaking. MSI also includes their new Instant OC Control Center software which gives users the ability the monitor and control system parameters from within Windows, with no need to reboot when making changes.

Other features of the MSI P67A-GD65 include USB3.0 and THX TruStudio PRO support, along with “Super Charger” which allows users to charge USB devices even when the system is powered down.

We found the layout of the MSI P67A-GD65 to be quite good and like the dark blue and black aesthetics.

Gigabyte P67A-UD7 Motherboard, Click To Enlarge

Next up we have the Gigabyte P67A-UD7. The P67A-UD7 is an enthusiast class, LGA1155 based motherboard for Sandy Bridge processors and will be Gigabyte’s flagship P67 mobo upon its arrival. It features a 24 phase CPU power design, Gigabyte’s “Ultra Durable 3” technology with two ounces copper layers within the PCB, ten SuperSpeed USB 3.0 ports, six SATA 6Gbps connectors, 3-way CrossFireX and SLI support, DualBIOS technology, and On/Off Charge support.

While the UD7 will be the flagship model at launch, targeting the enthusiast and extreme overclocking market all of Gigabyte’s P67 boards (UD7, UD5, UD4, UD3P) will come with the new black PCB. The H67A-UD3H still sports Gigabyte’s traditional blue color scheme.

Inside the box, Gigabyte provides an accessory bundle fitting for an enthusiast class product as well. The UD7 comes with a user manual, quick installation guide, driver disc, six SATA cables, I/O shield, dual eSATA bracket, 2-way SLI bridge, and a 3-way SLI bridge.


Sandy Bridge Coolers and Memory

Intel will be offering two coolers with new Sandy Bridge based processors, a basic circular cooler that’s identical to the model included with Lynnfield-based processors will accompany non-K SKUs and a more capable tower-type model will come with unlocked K SKUs, like the ones we’ve tested here.

Intel XTS100H Cooler

There’s nothing new to report with regard to the basic cooler, but the tower-type Intel XTS100H is a different story. The XTS100H has three, thick copper heatipes that run though a solid copper base, into an array of densely packed aluminum heatsink fins. A 92mm fan sits at the front, with a speed controller switch at the very top. The switch has two positions—Q for quiet and P for performance. In quiet mode, the cooler is just that, quiet. In performance mode, the fan can spin up considerably when the CPU is under load, but it’s not terribly loud.

The XTS100H includes a mounting plate that must be affixed to the underside of the CPU socket and four thumb screws hold the cooler firmly in place. We should note that although Sandy Bridge uses a new 1155 pin socket, the coolers use the same mounting holes socket 1156.

Corsair Vengeance 8GB Memory Kit, Model CMZ8GX3M2A1600C9

Patriot Memory Division 2 Viper Extreme 4GB Memory Kit, Model PXD34G1866ELK

As was the case when Nehalem and Lynnfield arrived, memory manufacturers are at the ready with low-voltage, dual-channel memory kits qualified for Sandy Bridge 6-seires chipset platforms. The two kits you see here come by way of Corsair and Patriot. The Corsair Vengeance kit includes 8GB (4GB x 2) of memory rated for operation at up to 1600MHz (C9) at 1.5v. The Patriot 4GB (2GB x 2) kit is rated for operation at up to 1866MHz (also C9) at 1.65v, although we found it would run with lower latencies at lower frequencies as well.


Test Setup and SiSoft SANDRA

Test System Configuration Notes: When configuring our test systems for this article, we first entered their respective system BIOSes and set each board to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set memory to DDR3-1333. The hard drives were then formatted, and Windows 7 Ultimate x64 was installed. When the Windows installation was complete, we updated the OS, and installed the drivers necessary for our components. Auto-Updating and Windows Defender were then disabled and we installed all of our benchmarking software, performed a disk clean-up, defragged the hard drives, and ran all of the tests.

HotHardware's Test Systems
Intel and AMD - Head To Head

System 1:
Core i7-2600K
(3.4GHz - Quad-Core)
Core i5-2500K
(3.3GHz - Quad-Core)

Intel DH67BL, DP67BG
Asus P8P67 Deluxe
Gigabyte P67A-UD7
(P67 Express Chipset) 

2x2GB Patriot DDR3-1866
(@ 1333MHz, CAS 8)

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows 7 x64
System 2:
Core i7-975
(3.33GHz - Quad-Core)
Core i7-980X
(3.33GHz - Six-Core)

Gigabyte EX58-UD5
(X58 Express Chipset)

3x2GB OCZ DDR3-1333
(@ 1333MHz, CAS 8)

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA 

Windows 7 x64
System 3:
Core i7 870
(2.93GHz - Quad-Core)
Core i5 750
(2.66GHz - Quad-Core)

Asus Maximus III Formula
(P55 Express Chipset)

2x2GB Kingston DDR3-1600
(@ 1333MHz, CAS 8)

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows 7 x64
System 4:
AMD Phenom II X4 975
(3.5GHz Quad-Core)
AMD Phenom II X6 1100T
(3.3GHz Six-Core)

MSI 890FX-GD75
(AMD 990FX Chipset) 

2x2GB Kingston DDR3-1600
(@ 1333MHz, CAS 8)

GeForce GTX 280
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA 

Windows 7 x64

Preliminary Testing with SiSoft SANDRA 2011B
Synthetic Benchmarks

We began our testing with SiSoftware's SANDRA 2011B, the System ANalyzer, Diagnostic and Reporting Assistant. We ran four of the built-in subsystem tests that partially comprise the SANDRA 2011 suite with Intel's new Core i5 and i7 "Sandy Bridge" processors (CPU Arithmetic, Multimedia, Memory Bandwidth, and Cache and Memory).  All of the scores reported below were taken with the processors running at their default clock speeds of 3.3GHz (2500K) and 3.4GHz (2600K) with 4GB of DDR3-1333 RAM running in dual-channel mode on the Asus P8P67 Deluxe motherboard.

Core i5-2500K

Core i5-2500K

Core i5-2500K
Memory Bandwidth

Core i5-2500K
Cache & Memory

Core i7-2700K

Core i7-2700K

Core i7-2700K
Memory Bandwidth

Core i7-2700K
Cache & Memory


The new Sandy Bridge-based Core i5-2500K and Core i7-2600K processors performed right about where we expected them too in the various SiSoft SANDRA tests. In the Processor Arithmetic and Multimedia benchmarks, the processors outpaced their previous-generation counterparts by a fair margin, when core counts were similar--the 6-core Core i7-980X remains Intel's fastest processor overall. The Core i5-2500K and Core i7-2600K also performed similarly in the Cache and Memory test and each one offered up about 16GB/s of peak memory bandwidth, when running in a dual-channel configuration at 1333MHz.

Futuremark PCMark Vantage

Next up, we ran a number of different test systems through Futuremark’s latest system performance metric, PCMark Vantage. PCMark Vantage runs through a host of different usage scenarios to simulate different types of workloads including High Definition TV and movie playback and manipulation, gaming, image editing and manipulation, music compression, communications, and productivity.  Most of the tests are multi-threaded as well, so the tests can exploit the additional resources offered by a multi-core CPU.

Futuremark PCMark Vantage
Simulated Application Performance

The new Core i5-2500K and Core i7-2600K processor performed very well in the various PCMark Vantage tests. Here, the Core i7-2600K kept pace with or beat the Core i7-975, which was previously Intel's fastest quad-core processor. And the Core i5-2500K made mince-meat of the Core i5-750, also a quad-core with no HT. AMD's processors, regardless of how many cores they had, finished well behind Sandy Bridge, and the 6-core Intel Core i7-980X remained the fastest CPU overall.

LAME MT Audio Encoding

In our custom LAME MT MP3 encoding test, we convert a large WAV file to the MP3 format, which is a popular scenario that many end users work with on a day-to-day basis to provide portability and storage of their digital audio content.  LAME is an open-source mid to high bit-rate and VBR (variable bit rate) MP3 audio encoder that is used widely around the world in a multitude of third party applications.

Audio Encoding

In this test, we created our own 223MB WAV file (a hallucinogenically-induced Grateful Dead jam) and converted it to the MP3 format using the multi-thread capable LAME MT application in single and multi-thread modes. Processing times are recorded below, listed in seconds. Shorter times equate to better performance.


According to our custom LAME MT benchmark, it appears the new Sandy Bridge microarchitecture is very well suited to audio encoding. The Core i5-2500K and Core i7-2600K put up the best scores in this test, outpacing even the Core i7-980X. This workload uses a maximum of only two threads, so the new Core i5-2500K and Core i7-2600K's architectural enhancements, in addition to their relatively high Turbo boost clock speeds, help propel them to the lead here. 


Cinebench R11.5 and POV-Ray

Cinebench R11.5 is a 3D rendering performance test based on Cinema 4D from Maxon. Cinema 4D is a 3D rendering and animation tool suite used by animation houses and producers like Sony Animation and many others.  It's very demanding of system processor resources and is an excellent gauge of pure computational throughput.

Cinebench R11.5 
3D Rendering

This is a multi-threaded, multi-processor aware benchmark that renders a photorealistic 3D scene (from the viral "No Keyframes" animation by AixSponza). This scene makes use of various algorithms to stress all available processor cores. The rate at which each test system was able to render the entire scene is represented in the graph below.


The new Core i5-2500K and Core i7-2600K performed very well in the Cinebench R11.5 benchmark. Here, the Core i7-2600K was easily the fastest Intel quad-core processor and the Core i5-2500K finished well ahead of the Core i5-750. Keep in mind, the Core i5-2500K does not have HyperThreading, so it can processes four fewer threads than the Core i7 processors can. Once again, there was no appreciable difference in performance between the various motherboards we tested and whether or not the Core i5's integrated processor graphics were used in lieu of a discrete GPU.

POV-Ray Performance
Ray Tracing

POV-Ray , or the Persistence of Vision Ray-Tracer, is an open source tool for creating realistically lit 3D graphics artwork. We tested with POV-Ray's standard 'one-CPU' and 'all-CPU' benchmarking tools on all of our test machines, and recorded the scores reported for each. Results are measured in pixels-per-second throughput; higher scores equate to better performance.


The performance trend in the POV-Ray benchmark essentially mirrored those of Cinebench. The Core i7-2600K was clearly the fastest of Intel's quad-core processors, falling victim to only the 6-core Core i7-980X. The Core i5-2500K was again significantly faster than the Core i5 as well.


3DMark06 and Vantage CPU Tests

3DMark06's built-in CPU test is a multi-threaded DirectX gaming metric that's useful for comparing relative performance between similarly equipped systems.  This test consists of two different 3D scenes that are processed with a software renderer that is dependent on the host CPU's performance.  Calculations that are normally reserved for your 3D accelerator are instead sent to the CPU for processing and rendering.  The frame-rate generated in each test is used to determine the final score.

Futuremark 3DMark06
Synthetic DirectX Gaming


The new Core i5-2500K and Core i7-2600K performed very well in the 3DMark06 CPU benchmark too. Here, only the Core i7 975 and 980X are able to outpace the even the Core i5-2500K and the Core i7-2600K outpaced everything but the 6-core 980X.

Futuremark 3DMark Vantage
Synthetic DirectX Gaming

3DMark Vantage's CPU Test 2 is a multi-threaded test designed for comparing relative game physics processing performance between systems.  This test consists of a single scene that features an air race of sorts, with a complex configuration of gates. There are aircraft in the test that trail smoke and collide with various cloth and soft-body obstacles, each other, and the ground. The smoke spreads, and reacts to the planes as they pass through it as well and all of this is calculated on the host CPU. 

The more taxing 3DMark Vantage CPU Test 2 put the Core i5-2500K just behind the Core i7-870 and Phenom II X6 1100T, but once again the Core i7-2600K pulls ahead of every other processor with the sole exception being the Core i7 980X.  We should also point out that all of the P67 based motherboards performed at nearly the same level again, as well.

Low-Res Gaming: Crysis and ETQW

For our next set of tests, we moved on to some in-game benchmarking with Crysis and Enemy Territory: Quake Wars. When testing processors with Crysis or ET:QW, we drop the resolution to 800x600, and reduce all of the in-game graphical options to their minimum values to isolate CPU and memory performance as much as possible. However, the in-game effects, which control the level of detail for the games' physics engines and particle systems, are left at their maximum values, since these actually do place some load on the CPU rather than GPU.

Low-Resolution Gaming: Crysis and ET: Quake Wars
Taking the GPU out of the Equation

The Crysis CPU benchmark had the Core i7-975 (quad-core) and 980X (6-core) processors outpacing the new Core i5-2500K and Core i7-2600K processors, but nothing from the AMD camp came close. ET:QW tests a different story, with the new Core i7-2600K taking the pole position, followed closely behind by the 980X.

Obviously, these are two instances where using the new Sandy Bridge-based Core i5 and i7's integrated graphics has a significant impact on performance, but note that both games ran with playable framerates at these low-quality settings. 

Hi-Res Gaming Multi-GPU Tests

For our next set of tests, we moved on to some high-resolution graphics benchmarking with 3DMark Vantage (DX10), ET:QW (OpenGL), and Metro 2033 (DX11). For these tests, we've tested a Core i7-2600K powered system outfitted with single, or dual Asus GeForce GTX 570 (SLI) or Radeon HD 6970 (CrossFire) graphics cards in the Asus P8P67 Deluxe motherboard. Due to the fact that these new Core i5 and i7 Sandy Bridge-based processors feature integrated PCI Express lanes, and the graphics cards essentially connect directly to the CPU, we wanted to see how graphics performance and multi-GPU scaling were affected in more GPU bound circumstances.


The Asus P8P67 Deluxe with a pair of Asus GeForce GTX 570 cards installed

High-Resolution Gaming: 3DMark Vantage
Taxing the Whole Rig

No problems to report here. Moving from one to two GPUs with a Core i7-2600K and Asus P8P67 Deluxe motherboard resulted in much better performance, with the total score and framerates scaling from between 81% to 93%, using 3DMark Vantage's "Extreme" testing preset.

Hi-Res Gaming Multi-GPU Tests (Cont.)

Next we moved on to some more high-resolution graphics benchmarking with ET:QW and Metro 2033, using the same Core i7-2600K / Asis P8P67 Deluxe based system and NVIDIA and ATI-based graphics cards.

High-Resolution Gaming: Metro 2033 and ET:QW
Taxing the Whole Rig

Once again we saw huge gains in performance moving from one to two GPUs. Both the GeForce GTX 570s and Radeon HD 6970s showed 92% performance improvements in Metro 2033, while the older, less taxing ET:QW showed improvement of 62% (Radeon HD 6970 CrossFire) and 78% (GeForce GTX 570 SLI).

HD Graphics vs. Discrete GPU - Gaming


For this next set of tests, we pitted the integrated processor graphics incorporated into the Sandy Bridge-based Intel Core i5-2500K and Core i7-2600K processors against a couple of the least expensive, current-generation discrete GPUs from NVIDIA and AMD, the GeForce GT 430 and Radeon HD 5550, respectively.

Intel HD Graphics vs. Discrete GPUs 
Gaming Benchmarks


At the high-quality, graphics intensive settings we used, the Intel HD 3000-series graphics integrated into the new Core i5-2500K and Core i7-2600K processors couldn't keep pace with either discrete GPU, plain and simple. The higher peak Turbo frequency for the integrated HD 3000 graphics core in the 4600K gave it a measurable lead over the 2500K, but neither offered anything close to playable framerates.

With that said, we consider these tests "worst case scenarios", with high resolutions and high levels of anti-aliasing and anisotropic filtering. The integrated Intel HD 3000-series GPU core has much less memory bandwidth than either of the discrete GPUs and it slows considerably with all this pixel processing giong on. Without any anti-aliasing enabled, the Intel HD 3000 graphic core actually in the Core i7-2600K actually put up 22.9 FPS in ET:QW and 16.72 FPS in L4D2 at 1920x1200. Since the L4D2 framerate remained relatively low, we also dropped the resolution a bit to 1680x1050 and were able to hit 20.39 FPS.

The moral of the story? While the integrated Intel HD 3000 series graphics core won't be competing with discrete GPUs in most games with high image quality settings, it is perfectly capable of some casual gaming.

With that said, throughout all of our testing, we only ran eight games on the Intel HD 3000 series graphics core. And while none of the titles we ran exhibited any issues, Intel's graphics drivers haven't been the most compatible in the past. Although the HD 3000 series core is more powerful than anything to come from Intel in the past, that doesn't necessarily mean it'll work with every game, even though it may have the horsepower to do so. Just something to keep in mind.


Quick Sync vs. Discrete GPU


As we've mentioned, the new Sandy Bridge-based Core i5-2500K and Core i7-2600K processors feature and integrated media encoding engine, dubbed Quick Sync, that's enabled when the integrated Intel HD graphics core is used. We tested the Intel Quick Sync encoder using a pre-release version of Cyberlink's MediaEspresso 6, which was coded to take advantage of Intel Quick Sync technology.

Intel Quick Sync Technology vs. Discrete GPU
Media Encoding

In this test, we took a 256MB AVCHD MTS file recorded using a Canon HD camcorder and converted it to an H.264 encoded MP4 compatible designed for use with an iPhone / iPad (or other portable media playback device).

The Quick Sync engine within the new Sandy Bridge processors offers exceptional encoding performance in terms of speed and quality. In our tests, enabling Quick Sync within MediaEspresso resulted in performance increases of 3.7x to 4.1x, smoking everything else we tested. It's a shame that Quick Sync can't be used when a discrete GPU is installed in a system with a single monitor though. Many of the users who build high-end systems with media encoding in mind aren't going to want to settle for integrated graphics, and may not run dual monitors. And since Windows 7 allows for multiple GPU types to be installed in a system, and Intel will allow Quick Sync to function in notebooks / laptops equipped with discrete GPUs with switchable graphics, we hope they figure out a way to enable it on the desktop as well.

1080P Flash Video Clip From YouTube (Full Screne)

SD Flash Video Clip from HULU (Full Screen)

We also played back numerous video types on the new Core i5-2500K and Core i7-2600K while using their integrated Intel HD 3000 series graphics core, including DVDs and a myriad of SD and HD clips of varying file types. All of the local content played back perfectly with very low CPU utilization. High resolutions Flash videos streamed from the web, however, were a bit more stressful on the system, however. We never lost frames or anything along those lines, but CPU utilization was relatively high in comparison to a discrete GPU. Using the latest Adobe Flash plug-in beta that's compatible with Intel's new graphics core, we saw CPU utilization in the mid-20% to high-30% range when playing back high-res Flash video, whereas utilization hovered in the 5% to 8% range with a GeForce GTX 570 installed in the test rig.


Total System Power Consumption

Throughout all of our benchmarking and testing, we also monitored how much power our test systems consumed using a power meter. Our goal was to give you all an idea as to how much power each configuration used while idling and while under a heavy workload. Please keep in mind that we were testing total system power consumption at the outlet here, not just the power being drawn by the processors alone.

Total System Power Consumption
Tested at the Outlet

The new Sandy Bridge based processors and companion 6-series chipsets offer power consumption that's nothing short of impressive. Under load, despite being arguably Intel's fastest quad-core desktop processor to date, the Core i7-2600K-based system consumed only 172 watts when using Intel's DP67BG motherboard. And that number jumps to only 196 watts when using the Asus P8P67 Deluxe. The only thing that consumed less power was a Core i5 clocked close to 1GHz lower. And look at what the Core i5-2500K can do when installed in the DH67BL and using integrated graphics--load power is lower than idle power on any other platform.

We should point out that the increased power consumption of the 2600K when installed on the Asus motherboard is a result of the additional integrated components of the P8P67 Deluxe in addition to slightly higher default voltages.
Performance Summary and Conclusion

Performance Summary: There are a number of performance related aspects to summarize here, including CPU, graphics, and motherboard / chipset performance. First let’s focus on CPU performance relative to previous generation Intel processors. The Core i7-2600K is arguably the fastest quad-core processor released from Intel to date. It hung with or surpassed the Core i7-975 and was clearly outpaced by only Intel’s 6-core processors. The Core i5-2500K couldn’t quite keep pace with previous generation Core i7 chips across the board, but it was right there alongside them in most tests, and it clearly outperformed the Lynnfield-based Core i5 processors. In relation to AMD’s current crop of processors, the new Sandy Bridge-based chips were clearly faster than AMD’s fastest quad-core, the Phenom II X4 970, and they were able to outpace the 6-core Phenom II X6 1100T in a number of tests as well.

In terms of graphics, the performance of Intel’s new HD Graphics 3000 core is vastly superior to anything the company has released to date, but it couldn’t keep pace with AMD’s or NVIDIA’s current-generation entry-level offerings. Intel’s new graphics core is perfectly capable of casual gaming and can even run many modern gaming titles at medium settings though, which is probably more than enough for a large portion of users. And the media encoding capabilities of the Quick Sync engine in the graphics core are nothing short of phenomenal. With Quick Sync enabled, the new Core i5-2500K and Core i7-2600K offered exception encoding performance.

As expected, motherboard performance doesn’t vary much with Sandy Bridge and the 6-series chipsets. Due to the fact that all of the traditional Northbridge functionality is now on the CPU itself, there aren’t many areas to optimize system performance at the chipset / motherboard level, and as such, quality motherboards like the ones we tested should perform similarly.

The quad-core Intel Sandy Bridge-based processors we have shown you here, along with their standard, non-K counterparts, should be hitting store shelves in roughly the next week or so, with dual-core Core i3 variants arriving in about another month. The price and feature breakdown of the mainstream Core i5 and Core i7 processors due to arrive is as follows.

As you can see, there is a small premium to be paid for an unlocked K SKUs, but for enthusiasts, that will be money well spent in our opinion. We should also note that in addition to the 95W processors listed here, Intel has lower-power 35W (dual-core), 45W, and 65W models coming down the pipeline as well. 6-Series chipset based motherboards should also be hitting the market in droves in the coming weeks at price points similar to the previous-gen 5-series chipsets that arrived alongside Lynnfield.

At the prices Intel will be asking for these processors, we’re nothing short of impressed. While $317 for the Core i7-2600K isn’t cheap, it is easily justified considering the chip is unlocked and offers performance that can only be bested by Intel’s ultra-expensive 6-core processors. And the $216 Core i5-2500K is easily the best performer in its segment as well. Couple these facts with the relatively low power consumption of the platform, excellent media transcoding performance, “free” DX10.1 graphics, and highly overclockable cores and Intel’s got a winner on their hands. About the only downside to these new processors is that they require yet another new socket. We also would like to see Quick Sync enabled when discrete graphics card is used.

Ultimately though, Intel’s new Sandy Bridge-based Core i5 and Core i7 processors and 6-series chipsets make for one heck of a potent combination. And we’ve only looked at the mainstream offerings here. We can’t wait to see what Intel has in store for the high-end.

  • Excellent Performance
  • Great Transcoding Performance
  • Highly Overclockable
  • Low Power Consumption
  • Competitive Pricing


    • Questionable Graphics Configurations
    • No Quick Sync With Discrete GPUs
    • Integrated Graphics Still Slower Than Low-End Discrete GPUs


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