Intel Core i7 975 Extreme Edition CPU Evaluation


With Nehalem architecture, Intel raised the CPU performance bar to a level that AMD has not been able to reach yet. Now Intel pushes it up even further by dropping a new top CPU on the market. But, is it worth the money?

Looking back at the past seven months, the Core i7 965 Extreme Edition is arguably the fastest stock consumer level CPU you can purchase right now. It is quite simply a monster. When we first looked at the i7 965 we were amazed at its power and headroom. For the first time we saw Lightwave single frame 1080i renders in less than three minutes and that is something that had never happened before. In fact, the quad-core Core i7 at 3.2 GHz even beat out the fastest 3.2 GHz Octa-Core Mac Pros out at the time [their times were just over 3 minutes for the same frame].

So how do you top performance like that? Well if you are Intel – you tweak the core of the CPU and bump up the multiplier and you create a D0 stepping CPU that features improved performance, reduced power consumption and what is most important right now; more overclocking headroom.

We have been lucky enough to get our hands on one of these and put it together with a GigaByte X58 Extreme mainboard for some testing at stock and overclocked speeds. So sit back and relax, and in the event of a water landing the person next to you may double as a flotation device… Ok now that I have gotten that out of my system lets dive into the i7 975 Xtreme Edition CPU from Intel.


As we received this sample directly from Intel, we were unable to evaluate the packaging. However, we believe that most of our readers are aware with Intel’s product packaging. The retail CPU will come inside a box manufactured with recyclable-friendly paper, while the plastic casing can be disposed in a separate bin [where available, Ed.].

Product Experience

Like stated before, we received the unit in an Intel standard evaluation CPU box – the retail experience would consist out of pulling the protective part of the retail box and removing the CPU and the cooler from the package. You would also get one of newly redesigned stickers for the case. If you’re purchasing a product priced at 999 greenbacks, you might as well put the sticker on the case. 

In our case, we simply applied ArticClean to prepare the IHS [Integrated Heat-Spreader or Heat-Sink] for installation, pulled up a lever on our GigaByte X58 Extreme motherboard, installed this sizeable CPU into the LGA-1366 processor socket, lowered the lever to lock the CPU in its place, positioned a Swiftec Apogee GTZ water-block and that concluded the installation part. Bear in mind that we do not see any point in shelling out a grand for the CPU if you’re not going to cool it with best possible way. In our case, since the goal is long-term stability with the high overclock, the solution to our dilema was simple – install water-cooling inside the system. 


As the D0 Stepping has been out for a couple of months we won’t delve into what is new there but will give you the dirty details on what you can expect performance wise from the new Bully on the Block.

The system we cobbled together for our testing was something of a beast, but that is to be expected if the CPU alone is a whole grand. We will experiment with the CPU in different platforms in the upcoming articles, but for now the goal was to compare progress made by Intel between i7 965 and 975 processors.

Intel Core i7 965 XE [C0 Stepping Engineering Sample]
Intel Core i7 975 XE [D0 Stepping Engineering Sample]
GIGABYTE X58 Extreme Mainboard [BIOS Version F8b]
6GB Qimonda Aneon DDR3 1600 [CL9]
6GB Kingston DDR3 1600 [used for overclocking testing]
2x Zotac GTX 280 AMP!  Edition 1GB GDDR3 GPUs [SLI-mode turned on]
LSI MegaRAID PCIe card
2x Seagate Cheetah 15k RPM 147GB SAS Drives [RAID 0]
Cooler Master UCP 1100W power supply
Swiftech H20 220 Apex Ultima Kit [with Apogee GTZ for i7]
Cooler Master ATCS 840 Enclosure
Microsoft Windows 7 Ultimate RC1


Continued on the next pages, Synthetic and Real-world testing, Overclocking, Value.

Performance results

Our testing followed the usual line of Synthetic and Real-World testing to cover both sides of the performance curve. For overclocking* we ran both a single “suicide shot" [the highest clock we could get a validation from CPU-Z] and a working overclock. The working overclock is the highest stable clock speed we were able to run all of our tests in series [no reboots] and get valid scores. The working clock is a better indication of OC headroom than a simple suicide screen. 

* Our results may differ from yours and are indicative of potential only. Since we are using an engineering sample CPU you may have better or worse results from an OEM or retail product. As with all overclocking the combination of hardware used and operating system can affect your maximum and stable OC.

With all that out of the way let’s dive into performance.


Our synthetic testing is the most easily reproducible testing as it is simply running a fixedcode on the hardware. This does not make it invalid but bear in mind that this is only a half of the picture. At BSN*, we strongly believe that using synthetic benchmarks is a standard way of testing equipment but it cannot be the only one. Just like automotive publications test the cars on a racetrack and real roads, we believe and we will insist on using both worlds in order to obtain complete picture of a product, regardless of what market that product is targeting. 

Of course no evaluation would be complete without throwing in the Futuremark numbers. We use both 3DMark Vantage and PCMark Vantage [in both x86 and x64 versions, where available] to cover all the possible bases there.

In 3DMark Vantage we were looking to see how well the CPU does with handling AI and Physics. We ran the test with GPU enabled Physics on and off to show the difference between the two CPUs with the system and the CPUs on their own.

The i7 975 does an impressive job in 3DMark without PhysX
The i7 shows off some impressive CPU power in 3DMark Vantage

Looking at the CPU scores here, they are simply staggering even without the nVidia PhysX the i7 is impressive. The 975 grants you an extra 1,000 CPU points over the 965 at stock speeds. Given the increase in default clock from 3.2 GHz to 3.33 GHz, we did not expect higher or smaller result. But it is more than obvious that the Turbo mode, present in all Core i7 processors is working hard on making those extra CPU cycles work.

PCMark Vantage
PCMark Vantage is a complete suite of tests that is designed to cover all of the uses a system would normally be put to. There are content creation tests, gaming, etc. We use it as a base line for comparison but it is not meant to be definitive.

PCMark shows interesting results
PCMark Vantage shows us a few interesting scores

Again we see a small performance lead for the 975 which is about what you would expect. What is interesting is the performance loss when running the 64-bit version. Here the 965 actually performs better than the 975 for some reason. Once a healthy overclock is running on the 975, the tables do certainly turn in favor of the 975 once again.

Sisoft Sandra 2009 SP3
Sandra is another synthetic that yields an approximation of performance at the component level. Here we can break down the CPU by specific tasks (arithmetic, multimedia, and multi-core efficiency) and give you an idea of how each should perform. We like SiSoft Sandra due to the fact that it also features GPGPU e.g. GPU computing tests, and the benchmark itself is very light on the system in terms of installation and overall size.

Sisoft's Sandra in action

As you would expect the 975 performs better than the 965 in almost every test, no questions asked. The only discrepency that was noted was the memory bandwidth test where the overclocked 975 did worse than the stock one.


Everest Ultimate 5.01
Everest was used in this case to show differences in available bandwidth to each CPU and again when the 975 XE was overclocked. But yeah, brace for impact – since we encountered issues when it comes to the performance part. See the picture below:

Everest Memory Bench

Again we see the 975 performs better, that is until we overclock the system. For some reason [and despite multiple runs] Everest would keep showing the 975 as significantly slower than the stock 975 and the 965. It read the memory bus at 3.8MHz and the BClock at 0.9, the CPU itself read a whopping 25.4MHz. Yes all of those read MHz. The performance scores of overclocked CPU certainly made us think of "Back to the Future" trilogy, since these numbers were last seen around 20 years ago, with 486 processors. Yes, even the allmighty Pentium  scored much higher than these clocks… we think that Tamas and his Lavalys team have serious work to do in order to put the support for i7 975.

HyperPi 0.99b
HyperPi allows you to run an instance of SuperPi on each CPU core, this is a good test of system stability as well as the speed of the Memory to CPU to HDD speed of a system.

HyperPi is another one where the System seemed to have a problem with the memory bus when overclocked. I am not certain why as of this writing but it looks like there is a bottleneck [or oversaturation] of the memory bus. It is possible that this is a mainboard issue and not a CPU issue but I have not been able to pin this one down yet. After Everest, this was the second application to experience some issues with the 975 processor. We cannot attribute this to the "engineering sample" marking on the CPU itself, but it looks like software vendors will require some work to get things up to speed. Literally.

Cinebench R10 x64:
Cinebench is from Maxon, the makers of Cinema 4D and is a synthetic rendering test. It also allows you to see the difference between rendering on one CPU core Vs Multiple CPU cores.

Cinebench Scores

While we saw memory performance issues with Sandra, Everest and HyperPi there was no problems with Cinebench. The i7 975 tacks on extra 1,000+ points to the multiple CPU score and a very nice 5,000 when overclocked. The single CPU scores were closer but still showed a performance improvement.


Continued on the next page: Real-world testing, Overclocking, Value.

Real-World Testing

When it comes to the subject of real-world testing, we want to know what is this CPU good for and how can you use it to either increase your productivity or level of entertainment.

LightWave 3D 9.3 x64
Lightwave 3D is one of the industry standards for 3D animation. As such it is a great test to show the ability of a CPU to render high-resolution images [1080i]. Our testing uses frame 32 of the Moonbase scene that is found on the Lightwave content CD1. We used classic cameras. 512MB segment memory, 7-Pass PLD AA filtering and a Gaussian Sharp reconstruction filter.



Lightwave was simple owned by the 975 again. The i7 975 at stock knocked an impressive 19 seconds off of the single frame render over the 965 while the overclocked 975 got us very close to a two minute render on the same frame.

AutoGK 2.55
AutoGK is a great “one stop” method for Transcoding video. We use a typical non-content protected DVD [at least 2 hours] and transcode it to XviD at 100% quality for both video and audio.


Talk about an upset; here the 965 is much faster than the 975 at stock or overclocked. We will be looking into this one to see why these numbers fell the way they did.

Gaming is very rarely CPU bound these days as most game developers are looking to dump as much eye candy as they can and push the title out the door you find that at any playable resolution you are more bound by the GPU. Despite that fact we still wanted to be able to show you how the i7 975 fares at gaming against it older bother the 965 and once again while overclocked.

FarCry2 is a game that was pushed for use on the i7. In fact there was even a contest that while great in scope and intent was a disaster in execution that centered on being able to win a copy of FarCry2 and even a few Core i7 CPUs.

For testing I used in game performance with frame rates captured by FRAPS. I ran through the first three errands you are sent on by your new benefactor. Settings are shown below.


As expected the frame rates were all within 1-2 FPS of each other. The game felt a little more snappy but the fate rates did not reflect this. This is a GPU-bound application, have no worries about that. The more GPUs you throw at Far Cry, the more frames you shall be awarded with.

F.E.A.R. 2 Project Origin
F.E.A.R. 2 follows in the same lines as the other episodes in the series it is a game that is intent on atmosphere and visuals. Unfortunately while the atmosphere is immersive the game play sometimes suffers. Still the visuals and the well coded AI make it excellent for testing.

My test run was through the Apartment rescue mission with frame being recorded from your entrance into the elevator until the pool scene.

As with FarCry2 the frame rates were almost identical really no improvement at normal resolutions here. Most of titles today are GPU-bound, and it would take a real simulaiton-intensive title to show any difference. Unfortunately, even with turbo-mode on, we did not notice any serious improvement in real-time strategy games.


While I am not a new comer to overclocking I am by no means an expert. However I have always found the i7 CPUs to be a considerable pain to overclock. This is especially true of the higher end varieties. With the 965 I was never able to get it stable over 3.9 GHz I could get into windows but it was far from stable.  The i7 975 was a little easier to work with. I was not as concerned with voltages as I had to be with the 965. In the end though I was not able to get more than 4236MHz [163MHz BClock x 26] with a stable OC at 4.183 [155MHz Bclock x 27].Voltages used for the stable OC were 1.3625 vCore, 1.880 CPU PLL, QPI PLL 1.36, QPI VTT 1.35, DRAM 1.54.

Working OC 4200

We will continue to tinker with the 975 and see if we can squeeze some more out of it. We will also be running a follow on evaluation of the GIGABYTE X58 Extreme used.


Concluded on the next page.


The i7 975 will not be inexpensive, as the top dog in the consumer CPU world Intel is going ask for and expect to get top dollar for this CPU. Is it worth that high-end price? The answer as always is subjective. Personally I would not fork out the extra cash for it unless I was in the high-end content creation business. The reason I say this is that there is no benefit to be had with the Core i7 975 over the older 965 or 940 if all you do is game. This is not to say that the i7 975 is not an amazing CPU, it will do pretty much everything you want and faster than anyone else can. I just do not know if the extra cost is worth it for most people. At the existing price point, you can easily fit two GeForce GTX 285 cards and the i7 920 CPU and overclock it to heavens high. But, if you need the fastest processor in the world for your workstation system, because you require every frame to be crunched, getting a water-cooled overclocked rig might be the right way to go. Seeing perfect stability at beyond 4 GHz clock is something that every content-creator should take a serious look at.


There is no doubt that Intel will retain the speed crown with the i7 975. Simply put there is nothing out there that can match it. All of the content creation applications we tested ran much faster than even the Core i7 965 and when you bump up the speed a little it will simple knock your socks off. But there is a down side to this, unfortunately the i7 975 will cost you a lot of money, this will put it out of the hands of many and as such it will remain the toy of the high-end enthusiast and professional designers for some time. I also feel that the i7 is pushing the limits of the 45nm process, the heat and power usage are pretty high with this CPU. I am looking forward to seeing what Intel can do with this design in the 32nm process. I have a feeling that we will see even more impressive performance once that shift happens.