Intel Core i7 975 Extreme

The Core i7 975 Extreme is top-end processor with a very exclusive price tag.  Its four cores run at 3.33 GHz, but it also has a Turbo mode, increasing the frequency to 3.46 GHz or even 3.60 GHz for apps that aren't optimised for multiple-core CPUs

In addition, hyper-threading is also available.  To keep it simple, this allows the CPU to add a virtual process to each core, so the OS acts as if it has eight cores available, rather than four.

Energy Consumption

This processor is hardly a model of energy efficiency.  While idle (when the computer isn't performing any tasks) we measured a consumption of 120 W.  That might not be the worst result ever, but it's still a long way behind the 800 and 700 series processors with produce figures 30-40 W below this level.  While active, it's hardly any better, with a maximum consumption of 258 W.

Performance: Applications

While energy efficiency might not be the i7 975's strong point, the same can't be said for its performance, where this processor demonstrated its comfort in every domain.  Its four threaded cores did particularly well at encoding video, where they got through our test in just 3 minutes 29 seconds.  For comparison, the Core i7 870 took 3 m 58 s.  For editing audio in Cubase 5.1, the results were just as impressive because we managed to use 205 compressors before the processor began to struggle; the i7 870 got stuck at 180.


Performance: Games

But do these good results mean that this is a processor that's only for audio and video pros?  It would seem not, as the results of our game tests were also impressive.  As a general rule, of the titles we used benefited from having four cores to play with.  The most obvious example was World in Conflict: Soviet Assault, where the average framerate of 57 fps, where the Core 2 Duo E8600, which was at the same frequency but had only two cores, only managed 45 fps.

There is one small hitch though: some games (ArmA 2, for instance), don't like it when you turn on hyper-threading and their performance falls as a result.  If you don't find some games a little jerky, try turning hyper-threading off, even if it will degrade performance in other apps.

View Performance Index Table