I'm sorry I should have posted more info in my previous post. Yes, I'm running Windows Vista x64 and Windows 7 x64, and Ubuntu..not that that matters.
Same issues, however, in the last ten minutes I think I may have figured out something that may be causing this. EDIT This is likely due to virtually all vendors using vista drivers for Windows 7, they work, well, heh, I did it running the Win7 for a long time. Anyways just pointing out it will be a good 3 months at least before we see solid Windows 7 drivers, at least, drivers that matter, like Gpu drivers. But the OS's are so similar in many ways, I can't say for sure how much better gaming will be on 7, although I can give my word in all my benchmarks, 17 games, Windows 7 is averaging a little over 5% increase in frame rate. Yeah, lots of work.
These 4890's throttle down, when not in use, to 250mhz. Now, I've read in places that these cards can sometimes downclock during gameplay, and their favorite spot is 500mhz. Mine both run 950mhz(stock is 850mhz), but that shouldn't matter. Now, it's possible while I'm playing NFS Shift, my Gpu (It only uses one) may be downclocking to 500mhz at times, and this would certainly account for the issues, and, well, it would be a very fitting explanation.
I'm going to open GpuZ, right now, and run NFS Shift on several races, and log it, and see if at any time during the races my Gpu downclocks, maybe I'm onto something here.
EDIT: I'd also like to add, just because someone is using an ATI Gpu, doesn't make them a fan of AMD. I know many people, and at one point myself, that are/were fans of ATI back before AMD bought the Gpu giant. It's unfair and extremely presumptuous to call someone an AMD fanboy/fanboi, or simply a supporter of AMD, just because they own an ATI Gpu. This should be obvious to any person of any intellect.
Anyways I'm going to get to work on that GpuZ/NFS Shift benchmark right now, on my new system, and the old, specs are below. Lets see what happens!