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Intel i7 975 Extreme in the lab

by on08 June 2009



Review: Fast, expensive and power hungry

After three quarters on the market, Intel has refreshed its i7 lineup. While the i7 965 Extreme will fade out, it is being replaced by the i7 975 Extreme, which comes in the D0 stepping and clocks only 133MHz faster at 3.33GHz. The D0 stepping does not offer any advantages for the normal customers, only slight improvements.


As you can see, still 8MB L3 Cache, 4x 256kB L2 Cache and 4x 32kB L1 Data and Instruction Cache. We have disabled Turbo Mode and Hyperthreading to make benches more fair. Besides, XP SP3 is not really suited for mutli-core systems and the CPU does fail to load multi-threading applications on it's physical CPU cores, which can decrease performance. We will check this behaviour again when Windows 7 hits the market. Our screenshots represents therefor the benchmnark setup.


Intel DX58SO "Smackover" (provided by Intel)
Intel X58/iCH10R

Intel Core i7 920  (provided by Intel)
Intel Core i7 965XE  (provided by Intel)
Intel Core i7 975XE  (provided by Intel)

Thermalright Ultra 120 eXtreme 1366 (provided by Thermalright)

Qimonda 3GB Kit PC3-8500U (provided by Qimonda)
Kingston 3GB Kit PC3-10600U KHX1600D3K3/2GX (provided by Kingston)

Graphics Card:
MSI R4850-2D1G-OC (provided by MSI)

Power supply:
PC Power & Cooling Silencer 500W (provided by PC Power & Cooling)

Hard disk:
Western Digital WD4000KD (provided by Ditech)

Case fans:
SilenX iXtrema Pro 14dB(A) (provided by

Cooler Master Stacker 831 Lite (provided by Cooler Master)

Overclocking is a piece of cake, just raise the Turbo Mode and you are good to go. Surprisingly the D0 stepping worked flawlessly without any voltage increases with a multiplier of 29 resulting in 3.86GHz.


If you want the same with Hyper-Threading enabled, you need to increase TDC und TDP values in your bios. We added 20A and 20W and here we go:


If you want go higher you need to disable the power saving features and the best cooling solution money can buy. We managed to go to 4.3GHz but power consumption went through the roof. Also, the temperature with our Thermalright cooler jumped to 98°C which is way too hot for 24/7 usage.

Click here for the full-size screenshot.

Our benchmarks are quite self-explanatory. While benching we find out that the new BIOS is considerable faster in lamemt, so we had the pleasure to re-test all CPUs again, to give you accurate results. Beside the usual benchmarks we included the Far Cry 2 Bench, which should show only the benefit of a faster CPU. With only the real cores enabled, the new CPU is not that much faster compared to the Q9 series, which are clocked a bit slower. The x264 optimizations for i7 do pay off. If you check out the results of Cinebench with the i7 overclocked at 4.3GHz, it's nearly twice as fast compared to the 3.0GHz Q9650.




3DMark 2003 ran at 1600x1200, 3DMark 2006 used defaults. As you can see, more CPU muscle doesn't really help. All results are quite close and 3DMark 2003 does not care much for a faster CPU.



With a reduced TDP rating of 130W the i7 series is still very power hungry. The Q9 series is now available with 65W. If you think it's twice as fast, think again, because it's not. The normal Q9650 with 95W TDP is still the most efficient cpu.




Intel i7 975 is without a doubt the fastest desktop CPU in the world. The new stepping did not help to reduce the massive power requirements, but it was enough to maintain the title of the fastest CPU around. Overclocking is a bit disappointing as it is in the range of an Phenom II, but of course Intel does charge a fortune for their premium CPUs. The CPU is already available for about €860,- in Euroland, and about $1000 in US.

As long as you are not into photoshopping or rendering on a professional basis, there is no reason to go for this platform. If you need performance with balanced power-consumption the Core 2 Quad Q9 series are still the CPUs to go for. For less performance you can buy for the same cash a whole machine with an AMD CPU but still with an high end graphics card which would be a better thing if you play games.

If the money is not an issue, if you don't care about the Amazon rainforest and power consumption that will go even to sky high 334W and you want the fastest CPU / Platform money can buy, this is the CPU for you. Everyone else should reconsider.

Core i7 remains the fastest and the most expensive CPU around but it is very clear that Nehalem generation won't reach mainstream before Lynnfield quad-core comes out with P55 platform in Q3 this year.

Last modified on 08 June 2009
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