Logo   Banner   TopRight
Intel Core i7 975 Extreme Edition Processor Review
Date: Jun 03, 2009
Author: Dave Altavilla
Introduction & Specifications

When you consider Intel's recent success at introducing new, cutting-edge processor architectures as of late, you can't help but appreciate the fact that the company is executing extremely well. The cold, hard fact of the matter is, even their last generation Core 2 architecture competes admirably with AMD's most recent update of the Phenom II, dollar for dollar and clock for clock.  In fact, Intel's Core 2 architecture has done so well, that further roll-out of Intel's newer Core i7 line-up has been limited, no doubt in part because Intel doesn't absolutely need their fledgling new chip architecture to compete vigorously with their rival. There's no question, AMD's Phenom II is a solid alternative to the Core 2 but playing catch-up to Intel's legacy architecture is still not a very exciting position to be in, obviously.

Thus far there have been a mere three different models of Intel's new Core i7 processor that have been released to any channel, OEM or retail - the Core i7-920, Core i7-940 and the flagship Core i7-965 Extreme Edition. With clock speeds starting at 2.66GHz and scaling to 3.2GHz, Intel's new Core i7 proverbially lights up anything from AMD's high end line-up right now, even comparing the chip's slowest speed bin, never mind at like clock speeds.  That said, the semiconductor business is pretty much a ruthless and relentless game of one-upsmanship; or in Intel's case currently, perhaps its two or three-up.  As such, you can be sure Intel is looking for another kill shot, whenever they can.

Today Intel is finally releasing new Core i7 models and speed bins to the market, as well as announcing a new flagship chip, the Core i7-975 Extreme Edition. Though it will definitely command a hefty price tag, at a stock clock speed of 3.33GHz and Intel Turbo Boost speeds at 3.45GHz (all cores) and 3.6GHz (single core), you can bet this new Core i7 is one hot-rod of a quad-core CPU.  In the pages ahead, we'll wind it out around the test track and show you what the fastest desktop processor on the planet can do when it's tuned up for a touch more horsepower at the factory and made ready for production.

Intel Core i7 975 Extreme Edition Processor - Engineering Sample

Intel Core i7 975 Extreme Edition Processor
Specifications & Features


Core Frequecy
QPI Link Frequency
Clock Multiplier
Intel Turbo Boost (Overclocking)
TDP (Thermal Design Power)
Number of CPU Cores
L2 Cache
L3 Cache
Max Processor Input Voltage (VID)
Manufacturing Process
Total Die Size
Instruction Set Extensions
Extended HALT State (C1E)
Execute Disable Bit (XD)
Enhanced Intel SpeedStep Technology (EIST)
Intel Virtualization Technology (VT)

Core i7 975 Extreme Edition

3.33 GHz
25X (unlocked)
1MB (256KX4)
8MB Intel Smart Cache
Flip Chip LGA1366

45nm Nehalem Quad-Core Processor Die Map

Intel Core i7 Products Launching This Week

The new Core i7 chips being announced today are Intel's new top-dog, the Core i7-975 Extreme Edition, as well as the new upper mid-range Core i7-950, which in fact will supplant the Core i7-940.  These new chips share identical Intel Nehalem-based microarchitectures, with the Core i7-975 offering a faster 6.4GT/sec QPI (Quick Path Interconnect) serial link to Intel's X58 Express Northbridge chipset, as well as a faster 3.33GHz core clock speed with a stock 25X multiplier and a 133MHz reference clock.  The Core i7 950 has a 23X stock multiplier that is locked for higher multiples but can be dialed down, while the Core i7-975 is unlocked for higher multiples as well, since it is an "Extreme Edition" product.

If you'd like a refresher course on Intel's Core i7 processor technology, we'd suggest taking a look at our Core i7 launch article, as well as our recent Core i7 overclocking article and how-to video.  These articles and our video spotlight will provide a solid reference, should you feel the need for a deep dive understanding of the technology, Intel's new platform, and how to maximize its performance.
Vital Signs and Overclocking

There is very little mystery behind what Intel was able to do with the Core i7 975.  What we're looking at here is a simple speed bump, though that's certainly not a bad thing.  In fact, though the base core speed of this new Core i7 is some 133MHz faster than its predecessor, it's not like Intel's previous high-end model, the Core i7 965 hasn't hit that clock speed before with Intel Turbo Boost overclocking technology.  That said, the Core i7 975 is turned up one click higher with a 25X stock multiplier (3.33GHz stock speed), which then affords a Turbo Boost multiplier of 26X for 3.45GHz.  For that matter, you could enable Turbo Boost at 27X on any individual core or all cores with the right motherboard.  Regardless, here are CPU-Z core identifier screen shots that give us a look at the new Core i7 975 at factory settings.

Intel Core i7 975 Extreme Edition CPU-Z Details 

Here you can also see that the QPI link (Quick Path Interconnect) for the Core i7 975 Extreme Edition is 3200MHz which offers 32GB/s of serial, bi-directional bandwidth, or a total of 6.4GT/s (GigaTransfers per second), as Intel likes to quantify it. In short, that's a bucket-load of bandwidth for any processor architecture. Also there are 4 cores shown here, capable of processing 8 threads via Intel Hyperthreading technology.  Finally, those cores are backed up by 32Kx4 instruction and 32Kx4 data L1 cache (32K per core), 256K of L2 cache per physical core (1MB total) and 8MB of shared L3 cache.

Beyond that, one very distinct notable is the fact that this revision of the chip is based on the Core i7's D0 stepping, which has been widely reported as having significantly more flexibility and potential in terms of overclocking.  Specifically, with respect to memory speeds, this stepping of the processor can offer some pretty magical combinations of both core clock speed and DDR-3 memory speeds.  As such, we set out to see what the Core i7 975 could do with a standard retail PIB cooler snapped on top to keep it stable.  First, let's look at thermals...

Intel Core i7 975 Extreme Edition Processor
Thermal Results

The Thermal Design Power (TDP) rating is meant to represent the maximum amount of power the cooling system needs to dissipate in order to prevent the chip from exceeding the maximum junction temperature. A TDP of 130W for the Core i975 means the heatsink/fan arrangement should be capable of dissipating 130 watts of heat or you'll risk malfunction due to overheating. In other words, it is a rating to represent how much cooling you'll need to keep the processor within its thermal margins during normal operation. While the TDP is neither a direct representation of the amount of power a chip uses, nor is it a direct indicator of the amount of heat it produces, it does provide an indicator about both of these metrics. It is also worth noting that TDP is specified for a family of processors. Although all standard Core i7 965 is also classified with a 130W TDP, the new Core i7 975 theoretically requires a bit more robust cooling due to its higher clock speed.  Regardless, even with a stock, Intel retail cooler, you can see that the chip still runs relatively very cool.

Intel Core i7 975 Extreme Edition Stock Speeds, Voltages, Temp.

Here we've got the Core i7 975 setup with a Turbo Boost clock speed of 3.6GHz and a 27X multiplier.  We've also have Cinebench R10 loaded up in the background pushing a 100% load on the processor.  We ran Cinebench in a loop, just to warm the core up a bit and then took this reading at full load.  In our open air test bench bench setup, the Core i7 975 Extreme Edition barely breaks a sweat at 47ºC.  Of course, within the confines of a PC chassis, core temps will likely scale a bit higher, but regardless, Intel's new core stepping offers plenty of thermal margin and very reasonable operating thermals.

Overclocking The Intel Core i7 975 Extreme Edition Processor
Pedal To The Metal

We're sure you are wondering if this new top-shelf Core i7 overclocks any better than its predecessor, so we put it through a quick round of overclocking. All overclocking was performed with the Intel stock cooler and a very modest 100mv voltage bump to allow the core to scale to 1.25V should it need the extra juice.

Intel Core i7 975 Extreme Edition Overclocked to 4.1GHz

Intel Core i7 975 Extreme Edition
Overclocked to 4.1GHz - 100% Load - DDR3 1968MHz

We were able to take the Core i7 975 Extreme Edition from its stock frequency of 3.33GHz at its stock reference clock of 133MHz, up to a maximum stable overclock of 4.1GHz with a reference clock of 164MHz. As you'll note in the above screen shots, we left the multiplier at its stock 25X setting but also did allow the memory controller to scale up to 1968MHz over its DDR3 interface.  This was accomplished using some rather special OCZ Blade DDR3-2133 (PC17000) memory from our friends at OCZ that we'll give you a sneak peek of next. 

We topped out at these processor and memory clock speeds with full stability and were able to run several iterations of Cinebench R10, as well as a full course of our entire benchmark suite.  As such, we'll include the benchmark numbers for the Core i7 975 at 4.1GHz for all of our benchmark results in the pages ahead.  Again this was all performed with a stock, retail Intel heatsink.  Impressive, to say the least.

Test System and SANDRA

Test System Configuration Notes: When configuring our test systems for this article, we first entered their respective system BIOS menus and set the motherboard to its "Optimized" or "High performance Defaults". We then saved the settings, re-entered the BIOS and set memory timings for either DDR2-1066 (AMD) with 5,5,5,15 timings, DDR3-1333 with 7,7,7,20 timings (Intel Core 2), or DDR3-1066 with 7,7,7,20 timings (Intel Core i7). The hard drives were then formatted, and Windows Vista Ultimate SP1 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 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 Extreme 975
(3.33GHz - Quad-Core)

Core i7 Extreme 965

(3.2GHz - Quad-Core)
Core i7 940
(2.93GHz - Quad-Core)
Core i7 920
(2.66GHz - Quad-Core)
Intel DX58SO
Gigabyte GA-EX58-Extreme

(X58 Express Chipset)
3x1GB Qimonda DDR3-1066
CL 7-7-7-20 - DDR3-1066
3x2GB OCZ Blade DDR3-2133 (OC Tests Only)
CL 8-9-8-30 - DDR3-2133
GeForce GTX 280
On-Board Ethernet
On-board Audio
WD150 "Raptor" HD
10,000 RPM SATA
Windows Vista Ultimate
NVIDIA Forceware v182.50
DirectX Redist (August 2008)
System 2:
Core 2 Extreme QX9770

(3.2GHz - Quad-Core)
Core 2 Quad QX9650
(2.66GHz - Quad-Core)
Asus P5E3 Premium
(X48 Express Chipset)
4x1GB Corsair DDR3-1800
CL 7-7-7-20 - DDR3-1333
GeForce GTX 280
On-Board Ethernet
On-board Audio
WD150 "Raptor" HD
10,000 RPM SATA
Windows Vista Ultimate
NVIDIA Forceware v182.50
DirectX Redist (August 2008)

System 3:
AMD Phenom X4 955

(3.2GHz Quad-Core)
AMD Phenom X4 940

(3.0GHz Quad-Core)
Asus M4A79T Deluxe
(AMD 790FX Chipset)
2x2GB Corsair DDR3-1600

CL 7-7-7-20 - DDR3-1333

GeForce GTX 280

On-Board Ethernet
On-board Audio
WD150 "Raptor" HD

10,000 RPM SATA
Windows Vista Ultimate

NVIDIA Forceware v182.50
DirectX Redist (August 2008)

Gigabyte's GA-EX58-Extreme Motherboard and OCZ's 6GB Blade PC3 17000 DDR3 Memory
Tools of the Overclocking Trade...

 Preliminary Testing with SiSoft SANDRA 2009 SP2
 Synthetic Benchmarks

We began our testing with SiSoftware's SANDRA 2009 SP1, the System ANalyzer, Diagnostic and Reporting Assistant. We ran three of the built-in subsystem tests that partially comprise the SANDRA 2009 SP1 suite with Intel's new Core i7 975 Extreme processor (CPU Arithmetic, Multimedia, Cache and Memory).  All of the scores reported below were taken with the processor running at its default clock speeds of 3.33GHz with 3GB of DDR3-1066 RAM running in triple-channel mode on the Intel DX58SO motherboard.

Processor Arithmetic
Core i7 975 Extreme

Core i7 975 Extreme

Cache and Memory
Core i7 975 Extreme

In all of the SANDRA tests we ran, the new Core i7 platform significantly outperformed all of the other systems in SiSoft's reference database.  In the CPU Arithmetic and Multi-Media benchmarks the Core i7 a little bit ahead of the Core i7 975 reference system within the SANDRA database.

The Core i7 also shined in all of the various memory-related benchmarks.  In its stock form using a DDR3-1066 triple-channel configuration, the Core i7 Extreme 975 put up an impressive 68.81GB/s of cache and memory bandwidth.  As you can see, having a smaller pool of L2 cache, along with a large shared 8MB L3 cache, offers plenty of available bandwidth for Intel's current Core i7 architecture. All three Core i7 scores in the database, including our Core i7 975 test system, out-paced legacy Core 2 Quad and current Phenom II bandwidth numbers by a wide margin.

PCMark Vantage Performance

Next up, we ran the new Core i7 975 through Futuremark‚Äôs latest system performance metric built especially for Windows Vista, PCMark Vantage. PCMark Vantage simulates a host of different usage scenarios for various types of mainstream user workloads, including High Definition TV and movie playback and manipulation, gaming, image editing and manipulation, music compression, communications, and office productivity tasks.  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 Business and Multimedia Application Performance

The first thing that jumps right out in these PCMark Vantage test results is the huge advantage the Core i7 powered systems have in the Gaming test versus the competition.   In the other tests, the Core i7 975's performance scales as you'd expect over the Core i7 965 Extreme chip, but by smaller margins, though sometimes as much as 7% or so. 

LAME MT and Kribibench Performance

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 in a multitude of third party audio conversion and editing applications and software suites.

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.

The new Core i7 975 processor offered the quickest encoding time according to our custom LAME MT benchmarks. The Core i7 Extreme 975 was 3 seconds faster than the Core i7 965 in the multi-threaded test (about 12%).  It's also interesting to note that the Core i7 920 at 2.66GHz is as fast as a Core 2 Extreme QX9770 in this test.  Unfortunately, AMD's fastest Phenom II is only able to hang with Intel's 3GHz Core 2 chip and is surpassed by the entire Core i7 family of CPUs. Our time for the Core i7 975 overclocked to 4.1GHz offers a glimpse of things to come as well.

Kribibench v1.1
CPU-Bound 3D Rendering

For this next batch of tests, we ran Kribibench v1.1, a 3D rendering benchmark produced by the folks at Adept Development.  Kribibench is an SSE aware software renderer where a 3D model is rendered and animated by the host CPU and the average frame rate is reported.  We used two of the included models with this benchmark: a "Sponge Explode" model consisting of over 19.2 million polygons and the test suite's "Ultra" model which is comprised of over 16 billion polys.

Intel's new Core i7 processors--regardless of their clock speed--were also the fastest of the bunch in the Kribibench rendering test and the Core i7 975 Extreme punched out about a 10% performance gain over its Core i7 965 counterpart.  And of course 4.1GHz the numbers pretty much speak for themselves.

Cinebench R10 and POV-Ray Rendering Performance

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.

It's not hard to see that the Intel Core i7 is in a class of its own, when it comes to raw computing throughput.  On a multi-core level the trend we've seen in our previous benchmark runs continues here with Cinebench.  Intel's fastest Core i7 975 processor is some 57% faster than AMD's fastest Phenom II.  Comparing single-threaded performance, Intel's new flagship is about 39% faster.  However, you have to remember, Intel's Core i7 Extreme Editions are currently also 4 times the price of a Phenom II 955.  A more balanced comparison from a pricing perspective would be the Core i7 920, though even then, you still have to factor in total platform costs, including Intel's more expensive triple-channel DDR3 implementation and the higher price of X58 chipset-based motherboards.

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.

Looking at POV-Ray ray-tracing performance, we see very much the same sort of spread amongst the Core i7 lineup, only this time the Core i7 975 chalks a smaller 5% gain over the Core i7 965.

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 i7 processors lead all other test systems in this test.  The Core i7 920 was once again able to pull out in front of the Core 2 Extreme QX9770 and the Core i7 965 and 975 are out in front by a sizable margin. The Core i7 975 offers an 8% advantage over Intel's next fastest chip.

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. 

More of the same can be seen in Futurmark's latest 3DMark Vantage processor test, though the Core i7 965 and 940 are more tightly coupled and Core i7 975 Extreme Edition leads the 965 by about 4%.

Low Res Gaming: Crysis and ET: Quake Wars

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 these game engines, 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 game's 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 Enemy Territory: Quake Wars
Taking the GPU out of the Equation

Our low-resolution Crysis and ET: Quake Wars benchmarks scale proportionately once again as expected, though the spread is a bit different, depending on which game engine you look at.  In Crysis, a notoriously piggish game engine that requires both a beefy CPU and a high-end GPU to run well, the gain observed for the Core i7 975 over the Core i7 965 is less prominent at about 4%.  On the other hand, Id's game engines in general are coded more efficiently and run more efficiently on a wider range of machines, with higher levels of processor cache and memory bandwidth historically offering better numbers in this type of test.  Here the Core i7 975 leads the next fastest CPU by about 14%.

Total System Power Consumption

Throughout all of our benchmarking and testing, we monitored how much power our Core i7 975 Extreme Edition test system consumed using a power meter. Our goal was to track how much power each configuration used while idling and while under a heavy host processor 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.  Regardless, if you look at the differentials between similarly configured test platforms, you can easily isolate the power consumption profile of each of the processors we tested.

 Total System Power Consumption
 Tested at the Outlet

In terms of idle power consumption, the new Core i7 processors are right in line with their Yorkfield-based Core 2 predecessors.  Only a few watts separate these architecturally very different platforms.  Under load, however, the Core i7-based systems consumed markedly more power.  The 3.33GHz Core i7 Extreme 975, for example, consumed 42 more watts than a Core 2 Extreme QX9770 while under a heavy workload.  Keep in mind though, the Core i7 offers a fair degree of upside performance at like frequencies versus Intel's legacy Core 2 architecture. 

So, while peak power consumption may be somewhat higher, the Core i7 platform is just as, if not more power efficient, in terms of performance-per-watt results, versus the Core 2 platform.  With that in mind, Intel's new 3.33GHz speed bump only consumes 5 watts more, fully loaded versus the Core i7 965.  At 4.1GHz overclocked with the Core i7 975, we're subjected to an increased power draw of up to 43 more watts under full load.  However, with a 23% clock speed boost, 15% more power consumption doesn't sound all that unreasonable.

Performance Analysis and Conclusion

Performance Summary:  To be perfectly frank, discussing the performance profile of the new Core i7 975 Extreme Edition is a tad on the mundane side.  In short, we're looking at a 4% clock speed boost that, by and large, offers a 4 - 5% performance increase versus the previous Intel high-end Extreme Edition Core i7 965.  In fact, the results were so linear and predictable, that we're rather impressed at the efficiency of IPC (Instructions Per Clock) production as clock speeds scaled with Intel's new leading-edge desktop processor architecture.  We witnessed virtually a 1:1 scaling of clock speed versus most benchmark results.  It was all a bit uneventful perhaps.  Then again, it was also refreshing to see a processor architecture scale so cleanly at various clock speeds.

In terms of overclocking, the new Core i7 975 processor stepping offered more headroom in top-end clock speed versus previous iterations of the architecture.  Whereas historically we've seen the Core i7 965 hit speeds of 4GHz with relative ease, the new Core i7 975 was able to settle down cleanly at 4.1GHz and handle our entire battery of benchmark tests with only a small voltage bump and a stock retail Intel heatsink keeping it cool; so cool in fact, it never broke 50ºC on our test bench under full load.


Right then; with all of our benchmark data points lined up, our thermal profiles and power consumption testing in check, what are the key take-aways with Intel's new Core i7 975 Extreme Edition processor?  To put it succinctly, Intel's new Core i7 975 is what it is; a 133MHz speed bump for a processor that runs in excess of 3.2GHz.  Does the Core i7 975 offer earth-shattering performance over its Core i7 965 predecessor?  Not at all really, but more of a very good thing is just plain goodness.

Intel's new Core i7 975 Extreme Edition processor is set to retail at an MSRP of $999, which is exactly where the Core i7 965 debuted upon its launch.  Further, the new Core i7 950 is set to retail at the same price as the Core i7 940 it will be replacing (current street pricing around $559 - $579) .  So, in reality, the Core i7 975 is another 133MHz of "free" performance for the product line, though clearly at $999, there are better values for the mainstream consumer in the Core i7 lineup, especially if you're into overclocking; take the Core i7 920 for example.

Nevertheless, when you get right down to it, the new Intel Core i7 975 Extreme Edition is quite simply the fastest X86 desktop processor on the market right now.  You can't find a faster CPU from any manufacturer on any desktop platform, or whether you consider yourself a "PC" or a Mac, for that matter.  What does that say of Intel's seemingly omnipotent new processor line-up?  You just have to hand it to them.  Enthusiasts and Average Joes alike can attest - Intel is simply "killing it" right now and the Core i7 975 Extreme Edition, though pricey to be sure, is the fastest desktop chip money can buy.  What else needs to be said?  As we've echoed many times over the years, the numbers speak for themselves.

OEM Access: Intel Talks Core i7 975 Extreme, Computex, Westmere and More Right Here.



  • Excellent Performance
  • Power Efficient
  • Highly Overclockable
  • Quiet PIB cooler
  • Smallish speed bump over Core i7 965
  • Pricey processor with relatively high total platform costs.

Content Property of HotHardware.com