GTX 275 Freezing/Crashes and Overall Underperforma

Alright. I've tried reading other fixes and I've decided to finally take the plunge and see if I can get some help specific to my machine.

I got my machine custom built a couple of years ago (I think. Time flies.) and it worked fine for quite a while and then it started having freezing and game crashing issues with EQ2. I read that had plenty of problems with certain combinations of hardware so I just lowered my graphics settings begrudgingly and got over it. However, it started crashing multiple games. These games were nothing spectacular compared to what I had run before, but the screen would blink black and I would get that bubble noting that my graphics driver had crashed. Sometimes I would get the momentary freezes with audio stutter. Unlike EQ2, the game would recover some or most of the time.

These problems have been increasing lately, even with older games while varying levels of settings that my computer should handle, but I just want to see if the games would at least work in some capacity. Again, most games are playable, it's just aggravating and I'm getting lower performance even when it's not freezing/crashing on me.

I've explored the idea of overheating, but benchmarks that I have run have been outright pitiful even when it's not hot. Also, I don't believe it was overheating, but I have downloaded and used some programs to manage my fan speeds instead of sitting at 40% until my card gets toasty.

I have also used driver sweeper and reinstalled the latest drivers (this has happened with drivers old and new, so I don't believe them to be the issue, but you know, step by step)

PSU is Corsair TX750W

DXDiag:
http://dl.dropbox.com/u/19497094/Pictures/Computer/DxDiag_08042011.txt

GPU-Z:

FurMark with AA 4x:

FurMark without AA:

  Thanks for reading over all of this and I hope somebody can help me. I do want to improve my systems performance by buying some upgrades, but first I'd let to get it back to optimal performance for what I have.