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Intel Clarkdale Core i5 Desktop Processor Debuts
Date: Jan 03, 2010
Author: Marco Chiappetta
Introduction and Specifications

Avid followers of the PC technology scene are no doubt familiar with the concept of CPU + GPU fusion. AMD has been talking about its Fusion project for years, which will feature advanced processor and graphics cores on a single chip. Well, we're not quite there yet, not on the desktop at least, but Intel is taking us one step closer with Clarkdale. Yes, we said Intel.

A couple of weeks ago, we evaluated Intel's Pinetrail platform for netbooks, which features an Atom CPU core, fused to a graphics processor on a single, monolithic die. Today, Intel is taking a similar approach in the desktop space with the company's much more powerful Clarkdale family of processors, although Clarkdale's integrated graphics processor isn't on-die--it is on the same package as the CPU though.

Clarkdale-based processors feature a number of cutting edge Intel technologies. For one, the processor cores are manufactured using a 32nm high-k process. They also feature Intel Turbo Mode technology, Hyper-Threading, AES acceleration, and Intel's latest graphics processing core, branded Intel HD Graphics, that also happens to house a memory controller and PCI Express connectivity.

The Clarkdale architecture will be used for a whole family of new processors in the Core i5, Core i3, and Pentium series. We've had one of the higher-end offerings in house for a few weeks, the Core i5 661, and have been putting it through its paces for most of that time. Read on for the full scoop...

Clarkdale Processor with Integrated Graphics, H57 Chipset

Intel Core i5 "Clarkdale" Desktop Processors
Specifications & Features


Clarkdale GPU and CPU Dies To Scale

Some may be confused into thinking Clarkdale is simply a die-shrink of Lynnfield with graphics attached, that is actually not the case. As the above image shows, Clarkdale's memory controller and PCI Express lanes are actually integrated into the graphics core, and not the CPU as they are with Lynnfield. Also note, the graphics core is physically larger than the CPU core, even though it is comprised of less than half the number of transistors. This is due to the fact that the graphics core is manufactured at 45nm whereas the CPU is manufactured at 32nm, as we've mentioned. To be more specific, the 32nm CPU die is comprised of 383 Million transistors, and is about 81mm2, while the 45nm graphics die is made up of roughly 177 Million transistors, and is 114mm2.

There's lots more to talk about though. First we'll cover the Core i5 661 and high-level features of Clarkdale, and will move on to the Intel HD Graphics engine, and new chipsets from there...

Clarkdale Core i5 661

Just to be clear, Clarkdale is the codename used to describe Intel's new mainstream desktop processor offerings based on the Nehalem microarchitecture, but manufactured on Intel's cutting edge 32nm process node. Arrandale is the mobile equivalent--we've got complete coverage of Arrandale posted here.

Core i5 661 Processor

Like other Nehalem derivatives, Clarkdale features Intel Turbo Boost and HyperThreading technologies, in addition to hardware acceleration for AES (Advanced Encryption Standard) and an on-chip graphics core.

As we've mentioned, the Clarkdale chips like the Core i5 661 we'll be looking at here will be produced using Intel's 32nm, 2nd Generation Hi-K process. The processors will feature two execution cores (dual-core), but with HyperThreading will be able to process up to 4 threads simultaneously. The processors will also feature up to 4MB of Intel Smart Cache, an Integrated Memory Controller (IMC) that support two-channels of DDR3 memory at officially supported speeds of up to 1333MHz, with integrated or discrete graphics support. We should note that when discreet graphics are used, the PCI Express lanes dedicated to the GPU may be arranged in either a 1x16 or 2x8 lane configuration, depending on the chipset being used--more on that later. Through new instructions, the Clarkdale-based processors also offer Advanced Encryption Standard (AES) acceleration, yet d the remain compatible with the LGA1156 Socket and 5-series chipset. Although a slew of new chipsets are being announced today as well.

There are few interesting things to note in regard to the integrated graphics core that will be used with Clarkdale and Arrandale. First, although the processors will be manufactured at 32nm, the graphics cores will be produced at 45nm. That means, of course, that the processors will feature multi-chip packages, and the CPU and GPU won't be merged on a single die. The IGP will be called the Intel HD Graphics core, and is derived from existing Intel graphics products. The new core, however, offers much improved performance and a number of new features, for Intel anyway. Mobile versions of the new IGP will also sport a Turbo mode of their own, that ratchets the clocks and voltage of the graphics core up or down, depending on the workload to conserve power or maximize performance. We have more details on the Intel HD Graphics core on the next page.

Core i5 661 CPU-Z Details

To get a glimpse of the Core i5 661's inner-workings, we fired up the latest version of CPU-Z and snapped a few images of the pertinent details.

The Core i5 661's default clock speed is 3.33GHz, but it clocks down to about 1.2GHz while idling to save power. The default clock speed is a result of its stock 25x multiplier and 133MHz base clock frequency (25 x 133MHz = 3.33GHz). With Turbo Mode enabled, however, the Core i5 661's frequency will peak at 3.6GHz. CPU-Z correctly reports that the Core i5 661 features 2 cores, but that the chip can process up to 4 threads, thank to Hyper-Threading technology.

The Cache configuration on the processors consists of 2 x 32K, 8-way associative L1 data caches, 2 x 32K, 4-way associative L1 instruction caches, 2 x 256K 8-way associative L2 caches, and 4MB of 16-way associative L3 caches--exactly half of what you'd find on a quad-core Nehalem derivative.

Overclocking The Core i5 661
Pedal To The Metal

Core i5 661 Overclocked to ~3.8GHz

We also set out to do a bit of overclocking with the new Core i5 661. We should point out that there are no "Extreme Edition" Core i5 processors, hence they are all multiplier locked for higher values and cannot be manually manipulated upwards to increase clock speeds. The only way to manually increase their frequencies is to increase the base clock speed, which by default runs at 133MHz.

To overclock the Core i5 661, we used the stock Intel cooler and an Asus P7H57D-V EVO motherboard. Tp begin, we first increased the processor's voltage to 1.38v and then increased the base clock frequency until our test system was no longer stable. Turbo mode was disabled to prevent any unwanted frequency spikes, but we left HyperThreading enabled. In the end, we came just shy of 3.8GHz, with a BCLK of 151MHz.

At that speed, the chip idled at around 39'C and peaked at about 68'C under load. We believe we were being held back, however, because any BCLK above 151MHz hung the system hard when Windows was loading. We'll be looking into this further, and will keep you appraised of the situation.

Intel HD Graphics Core

There is little doubt that Intel's previous generation integrated graphics cores left more than a little to be desired, when it came to offloading the CPU of multimedia and gaming tasks. In fact, gaming on an Intel IGP has historically been essentially non-existent, unless Farmville is your kind of thing.

It was only recently that Intel began offering a solid HD video experience on with their G45 series chipset and even then, you needed a decent processor to help with some of the heavy lifting. However, for this iteration of integrated graphics solutions, if Intel was going to directly bolt this technology to the CPU on the same substrate, they had to beef things up a bit and indeed they have.

Intel HD Graphics Feature Breakdown

Culled from Intel's slide deck, above is a feature breakdown of what Intel is now calling "HD Graphics", the DirectX 10-class GPU core that resides on the Clarkdale CPU package itself. Intel has outfitted the GPU with 12 shader cores or execution units as they call them, in conjunction with some fairly major upgrades to the architecture. Techniques and algorithms like Hierarchical Z-Buffer and Fast Z clear have been incorporated into competitive discrete GPU solutions from AMD and NVIDIA for many years now but are just making their way into Intel's IGP (Integrated Graphics Processor) solutions. Specifically, these two features afford the GPU core more efficient operation in the rendering pipeline, allowing pixels that aren't needed to be cast out of the rendering workload early, in addition to clearing buffer memory more quickly for faster read/write operations.

Intel HD Graphics, On-Chip--not on Die--IGP

The GPU core clock has also been turned up to 900MHz with dynamic clock gating support or "graphics turbo" on mobile variants that, like the processor core itself, allows clock speeds to be ramped up or down based on workload. Finally, Intel has also added dual simultaneous HDMI output support for the platform as well.

Intel has also buffed out the feature stack as well with respect to HD video processing, now offering dual video decode for picture-in-picture TV tuners and other applications and higher 12-bit per component color depth in support of the full HDMI 1.3 specification. DisplayPort support has also been dropped in, in addition to Dolby TrueHD and DTS-HD audio.

A Closer Look At Intel's New HD Graphics Control Panel

All told the enhancements to the graphics and media capabilities of Intel's HD Graphics solution are significant and bring a very much welcomed new level of functionality to the solution that previously Intel simply didn't compete well in versus competitive IGPs on the market. Intel's capabilities have vastly improved in this area. And of course, we'll also chart out some of the hard benchmark data for you on this, in the pages ahead.

A New Family of Chipsets

To compliment the new Core i5, i3 and Pentium series processors, Intel is also introducing a handful of new chipsets. They all have a number of shared features, but each is targeted at a different market segment.

Because the Core i5, i3 and Pentium series processors series processors feature integrated memory controllers and PCI Express connectivity, in addition to graphics, virtually all of the functionality previously integrated into a northbridge is now on the CPU die or at least on the same package. As such, the new chipsets designed for Clarkdale are fundamentally similar to a southbridge chip, but linked directly to the processor.

The above block diagram shows the new H57 chipset; the H55 is essentially the same, sans a couple of USB and PCIe ports and support for Intel Rapid Storage Technology.  As you can see, the chipset links to the processor via a DMI interface in addition to an FDI, or Flexible Display Interface. Memory and some PCI Express expansion cards--most likely graphics card(s)--connect directly to the CPU. The H57 Express itself features 14 USB 2.0 ports, an additional 8 lanes of PCE Express Gen 1 connectivity, and integrated GigE MAC, HD audio, 6 SATA ports, and a number of digital display ports, to accommodate HDMI, DisplayPort, and DVI outputs on the motherboard.

The entire family of new chipsets debuting alongside Clarkdale is outlined in the chart above.  The H57 and H55 are targeted at home desktop users, while the Q57 is designed for the enterprise space where features like Anti-Theft and Active Management Technologies are more desirable, and more likely to be used. Overall, the H57 and H55 differ in only three ways. The H57 supports up to 14 USB 2.0 ports, while the H55 supports 12. The H57 has two additional PCI Express 2.0 ports. And the H55 lacks support for Intel Rapid Storage Technology. The P55 is listed in the chart because it is technically compatible with Clarkdale-based processors, but because the P55 lacks the necessary features to expose Clarkdale's integrated Intel HD Graphics core, it's not likely to be popular choice for Clarkdale-based systems.

Clarkdale Motherboards: Asus, Intel

To test the new Core i5 661, we got our hands on a couple of new motherboards--one from Intel and the other from Asus.



Asus P7H57D-V EVO ATX Motherboard

The board you see pictured here is the Asus P7H57D-V EVO. Like other EVO-branded boards, this one sports a dark PCB, with some aggressive looking heatsinks on the VRM and chipset. It has a hybrid 12 phase power configuration, and the VRM is made up of low RDS (on) MOSFETs, Ferrite core chokes, and 100% Japanese-made, high quality conductive polymer caps. Expansion slots include dual PCI Express x16 slots (@ x8 when both slots are used), three PCI Express x1 slots (one Gen 2, and two Gen 1s), and two standard PCI slots.

Other interesting features of the Asus P7H57D-V EVO include an integrated Asus T.Probe chip which detects and balances power phase loads and temperatures in real-time. According to Asus, T.Probe allows the components in the VRM to run cooler with more even power distribution across phases, which should extend the board's lifespan while offering more stable power output as well.

The Asus P7H57D-V EVO also sports Asus' Turbo V EVO chip for real-time overclocking and tweaking assistance, but manual overclocking is obviously supported as well. Another noteworthy feature of the Asus P7H57D-V EVO in the integration of a Marvell 9123 6G SATA controller. Instead of connecting directly to the PCIe Gen 1 lanes available in the P55 chipset though, the Marvell 6G SATA controller is linked to the chipset via a PLX8613 PCI Express Gen 2 bridge. The PLX8613 connected to the H57 via four Gen 1 PCIe lanes, but links to the Marvell controller via single Gen 2 lane. Although the 500MB/s available with a single Gen 2 PCIe lane is 100MB/s lower than the SATA 6G spec, Asus notes, "The 600MB/s is the theoretical transfer rate. Due to the limitation of current SATA 6Gb/s HDDs, the 500MB/s is quite Enough for the SATA 6Gb/s HDDs." The board also sports a NEC USB 3.0 controller as well, which also connects to the chipset PLX8613 bridge.

A quick glance at the P7H57D-V EVO's backplane reveals all of the connectors we've come to expect from a well-appointed motherboard, in addition to all of the digital display outputs necessary to compliment the Core i5 661, and other Clarkdale-based processors. We should point out, this is the motherboard we used throughout our testing.



Intel DH55TC Micro-ATM Motherboard

Intel also sent over a board based on the H55 chipset, the Micro-ATX DH55TC. The DH55TC is built on a dark colored PCB, with blue and white accents--like many of Intel's recent motherboards. Generally speaking, the layout of the board is good and there are no major components that impinge on any others. The VRM on the board is bare and free of additional cooler, but the H55 chipset gets its own heatsink. While the heatsink on the chipset may appear small, especially in comparison to some other motherboards, we should note that even with this relatively miniscule heatsink, the chipset got just warm to the touch, even after hours of testing.

If you look at the various shots of the DH55TC above, you'll see that it is mostly legacy free, and devoid and any IDE or floppy connectors, but PS2 connector is present. Its backplane is home to an assortment of USB, audio, and Ethernet jacks, in addition to an array of display outputs. It offers support for up to four DIMMs, and expansion slots include one PCI Express x16 slot, two PCIe x1 slots, and a single PCI slot. Of course, all of the features inherent to the H55 express chipset, which we explained on the previous page, are exploited as well.

Test Setup and 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 timings for either DDR3-1333 with 8,8,8,24 timings. 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 i5 661
(3.33GHz - Dual-Core)

Asus P7H57D-V EVO
(H57 Express Chipset) 

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

GeForce GTX 280 or IGP 
On-Board Ethernet
On-board Audio

WD150 "Raptor" HD
10,000 RPM SATA

Windows 7 x64 
NVIDIA Forceware v190.62
System 2: 
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 
NVIDIA Forceware v190.62
System 3: 
Core i7 920
(2.66GHz - Quad-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 
NVIDIA Forceware v190.62
System 4:
Core 2 Q9650
(3GHz - Quad-Core)
Core 2 Quad Q9400
(2.66GHz - Quad-Core)

Gigabyte X48T-DQ6
(X48 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 
NVIDIA Forceware v190.62
System 5:
AMD Phenom II X4 965
(3.4GHz Quad-Core)

Asus M4A79T Deluxe
(AMD 790FX 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 
NVIDIA Forceware v190.62
 Preliminary Testing with SiSoft SANDRA 2010c
 Synthetic Benchmarks

We began our testing with SiSoftware's SANDRA 2010c, the System ANalyzer, Diagnostic and Reporting Assistant. We ran three of the built-in subsystem tests that partially comprise the suite with Intel's new Core i5 661 processor (CPU Arithmetic, Multimedia, and Memory Bandwidth).  All of the scores reported below were taken with the processor running at its default clock speed of 3.33GHz with 4GB of DDR3-1333 RAM running in dual-channel mode, although Turbo mode was enabled as well.

Processor Arithmetic
Core i5 661

Processor Multimedia
Core i5 661

Memory Bandwidth
Core i5 661

The new Intel Core i5 661 performed well in the SiSoft SANDRA benchmarks that we ran.  Because the processor is HT enabled, it can process up to 4 threads simultaneously on its two physical execution cores, thus it performed in-line with some of Intel's quad-core processors and was clearly the fastest Intel dual-core CPU. Memory bandwidth was also very good, with numbers approaching the 12GB/s range.

PCMark Vantage

Next up, we ran a number of different test systems through Futuremark‚Äôs latest system performance evaluation tool, 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 quad-core CPU.

Futuremark PCMark Vantage
Simulated Application Performance

Whether using the Intel HD Graphics IGP or a discreet GeForce GTX 280, the new Core i5 661 performs quite well. As you can see, the dual-core Core i5 661 performs about on par with or somewhat better than the quad-core Phenom II X4 and clearly outpaces the Core 2 processors.

LAME MT and x264 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.


A single instance of LAME MT working a single file can utilize a maximum of only two threads, hence the Core i5 661's strong performance here. In our custom LAME MT test, the Core i5 661 leads the pack.

x264 Video Encoding Benchmark
H.264 HD Video Encoding

The x264 benchmark measures how fast a system can encode a short, DVD quality MPEG-2 video clip into a high-quality H.264 HD video clip. The application reports the compression results in frames per second for each pass of the video encoding process, and it is threaded so it can take advantage of the additional resources afforded by multi-core processors.

Although the Core i5 661 can process four threads simultaneously, and it's the highest clocked CPU on the bunch, it couldn't quite keep pace with the true quad-cores in the x264 video encoding benchmark. The Core i5 661 certainly performed well though, especially considering it's a dual-cpu CPU.

Cinebench R10 and POV-Ray

Cinebench R10 is an OpenGL 3D rendering performance test based on Cinema 4D from Maxon. Cinema 4D is a 3D rendering and animation tool suite used by 3D 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 R10
3D Rendering

This is a multi-threaded, multi-processor aware benchmark that renders a single 3D scene and tracks the length of the entire process. The rate at which each test system was able to render the entire scene is represented in the graph below.


The new Core i5 661 rocked Cinebench's single-threaded test, placing second overall thanks to its relatively high frequency (and the micro-architecture, of course). In the multi-threaded test though, despite being HT enabled, the Core i5 661 couldn't hang with the true quad-cores.

POV-Ray Performance
Ray Tracing

POV-Ray , or the Persistence of Vision Ray-Tracer, is a top-notch open source tool for creating realistically lit 3D graphics artwork. We tested with POV-Ray's standard 'all-CPU' benchmarking tool 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.

POV-Ray tells essentially the same story as Cinebench. The Core i5 661 puts up some impressive numbers in the single-threaded test, but falls victim to the quad-cores in the multi-threaded test.

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 661 just missed the mark set by the Core 2 Quad Q9400, according to 3DMark06's CPU built-in CPU benchmark, and trails the rest of the pack. Not bad considering it's got half the cores of all of the chips. 

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 story doesn't change with 3DMark Vantage's CPU Test 2. Here, the Core i5 661 once again trails the pack, but puts up some really good numbers considering the processor has only two cores.

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--Somtimes

You'll notice, that even though the in-game graphics options are set to their minimums and the games are running at a low-resolution, the Intel HD Graphics processor incorporated onto the Core i5 661, and the AMD 785G for that matter, severely limits performance. When using a discreet graphics card, however, the Core i5 661 performs very well, hanging with or besting the Phenom II X4 and finishing about on par with the Core 2 Quad Q9650.

GPU Performance: 3DMark Vantage

We also did a bit of testing designed to tax the Intel HD Graphics incorporated onto the Core i5 661. For the next few tests, we pit the Core i5 661 and its Intel HD IGP against the Phenom II X4 965 and AMD 785G combo, running 3DMark Vantage and ET: Quake Wars at 1280x1024.

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

Somewhat surprisingly, the Intel HD Graphics core, as it is configured on the Core i5 661, handily outpaced the AMD 785G in 3DMark Vantage. The individual GPU Test scores show the Intel HD Graphics core with the largest lead in Test 1, where it's nearly twice as fast. Fast, of course, is a relatively term here.

GPU Performance: ETQW and Multimedia

For our next set of tests, we moved on to some in-game tests with Enemy Territory: Quake Wars running in its High Quality mode, at a resolution of 1280x1024. Then we move on to some multi-media tests using a handful of videos, encoded using MPEG 2 or H.264 to see how the Intel HD Graphics core handles the workload.

High-Resolution Gaming: Enemy Territory: Quake Wars
Taxing the GPU

Although we wouldn't exactly call the 20.7 frames per second put up by the Intel HD Graphics core found on the Core i5 661 playable, the framerate was high enough to pull ahead of the 785G. With a reduction in image quality, older games like this should be playable on Intel HD Graphics. And casual games, like those splattered all over Facebook, will have no problem running either.

"RAD" MPEG SD Video, Windows Media Player

"Max Payne" H.264 HD Video, Windows Media Player

"Casino Royale" H.264 Blu-Ray HD Rip, Power DVD 9 

Intel obviously put a significant amount of effort into the Intel HD Graphics core's multi-media capabilities. As you can see in the screenshots above, with all of the different video types, the load being placed on the Core i5 661 CPU is nice and low, ranging from single-digit percentages on up to about 35%. We also tested DVD playback, M4V files, and a myriad of other file types and all of them played very well on the Intel HD Graphics core.

Power Consumption

We'd like to cover a few final data points before bringing this article to a close. Throughout all of our benchmarking and testing, we 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 Core i5 661 is one heck of a power-friendly processor, when paired with the right components. With the Core i5 661 utilizing its integrated graphics core, it is the lowest power option by a wide margin. Its idle power is close to the Phenom / 785G combo, but the Core i5 661's load power is significantly lower than anything else. When paired with a powerful discreet graphics card like the GTX 280, total system power consumption goes way up, but once again the Core i5 661 consumes the least amount of power, although by a much smaller margin.

Summary and Conclusion

Performance Summary: To Core i5 661 is the fastest Intel dual-core processor we've ever tested, until the Core i5 670 lands in the lab that is. But that's a story for another day. Looking back at our numbers, it's clear that the Core i5 661 is a strong performer. Although the chip sports only two physical execution cores, the processor's ability to leverage HyperThreading to process up to four threads makes it act like a quad-core in some circumstances. Overall, the Core i5 661's performance falls somewhere in between a Core 2 Quad Q9650 and Q9400 in real-world application performance, although in situations where only one or two threads are being executed the Core i5 661 can be significantly faster thanks to its more advanced cores and high frequency--i.e. in the LAME MT benchmark.

When working in conjunction with its integrated Intel HD Graphics engine, the Core i5 661 also performs well, and compares favorably to AMD's top-of-line Phenom II, when it's paired to the AMD 785G IGP. Although AMD's platform pulled ahead in the low-res ET:QW test, Intel's solution led everywhere else. In our multimedia testing, the Core i5 661 + Intel HD Graphics combo also handled SD and HD video playback exceptionally well.

The Core i5 661 is an interesting animal. It's a dual-core processor that performs like a quad-core, for the most part anyway. Thanks to its high-clocked execution cores, which also support Hyper-Threading, desktop application performance is very good. We also feel that the processor's integrated Intel HD Graphics core is Intel's best graphics solution to date. While it may not be able to burn through modern 3D gaming titles, the Intel HD Graphics engine is more than powerful enough for typical office duties and it performed very well with a variety of multimedia workloads. The Intel HD Graphics engine also lived up to its name, and handled a variety of HD videos with aplomb.

Although we focused on the Core i5 661 in this article, Intel is actually announcing a number of new Clarkdale-based processors today.  Here's the complete breakdown of Clarkdale-based desktop processors that are on the way...

As you can see, the Core i5 661 is near the top of the heap, with only the i5 670 ranking higher. The Core i5 661 is priced at $196 in 1K quantities, which is identical to the i5 660. Although priced the same, the 661 differs from the 660 in that the 661's integrated Intel HD graphics engine is clocked higher (900MHz vs. 733MHz), hence the chip's higher TDP. The Core i3 series processors you see listed here, while also being clocked lower, lack support for Intel's Turbo Mode technology--so that clock speeds you see are the clock speeds that you get.

Strictly talking in terms of the technology, Clarkdale is a very cool product. Performance is very good, the chips are power friendly, and they represent the bleeding edge of desktop computing (32nm process, on-chip graphics, etc.) But their naming convention is definitely going to confuse some consumers and pricing is difficult to understand.  As it stands now, Intel has quad-core and dual-core Core i5 processors, some with and some without integrated graphics. And some of the chips have faster clocked IGPs than others. With regard to pricing, these new Core i5 chipst are more affordable and faster than the fastest Wolfdales, and they also offer more features, but at the same time they're pricier than AMD's fastest quad-core Phenom IIs, which perform better in many circumstances. We can see why these new chips are priced as they are, but would have been more impresses had they been somewhat more affordable.

Ultimately though, Intel should be commended for fusing their best graphics engine to date with their most cutting edge dual-core processor. Clarkdale-based Core i5 and Core i3 processors may not break any benchmark records, but they're excellent options for mainstream, lower-power systems, well suited to a wide-range of usage models. If you're looking for components to build a fast, affordable dual-core rig, and will be happy with integrated graphics, your search may be over.


  • Good Performance
  • Low Power Consumption
  • 32nm CPU Core
  • On-Chip DX10 Graphics
  • Solid Multimedia Capabilities


  • Questionable Pricing
  • IGP Still Not Great For 3D Gaming
  • Confusing Naming Scheme


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