Quote Originally Posted by MpG View Post
For the record, the QX9770 is specced for 400FSB to begin with. Also, you might be surprised at how little a 400FSB will bottleneck a single Quad-core processor, even at the 4.0GHz mark. I remember back when the QX6800 first came out, and people were wondering about the 266FSB being an issue.
more threads, faster video cards, more memory use and it will be a big problem.

here is one that tested som interesting OC

http://forums.guru3d.com/showthread.php?p=2740928

I think I have found the culprit: It's the FSB!

I did the following:
- changed my CPU clock from 2400 (9*266) to 1600 (6*266) - no change, 27 FPS
- changed my memory clock from 400 to 266 - no change, 27 FPS
- changed my FSB from 266 to 333 - success, 34 FPS

The FPS actually changed exactly according to my FSB change - a 25% increase in both cases.
It might still be memory bandwidth though, since with Intel CPUs the FSB is the limiting factor.
I have never actually seen any game that is limited by FSB or memory bandwidth nor any mention of such behaviour. I think we have found a new type of bottleneck here.

EDIT: I just ran another test: I decreased the memory clock to 266 while keeping the FSB at 333: Still 34 FPS. So it actually is the FSB.
Time for Nehalem, I'd say.