What is the most power CPU that my GA-X38T-DQ6 LGA 775 will run?

Just as the title states please. I have a Over clocked Core 2 Quad core processor running at 3.2 GHZ, some nice DDR3, an 8800 GT yadda yadda, I've had this for about a year and a half now somewhere therebouts.

The computer is fine, but I'm looking to eliminate the hiccups in my higher end games so I can run them at 60fps. I don't play anything higher than 1280x1024, so I'm not sure if I have a video card issue, or more so the cpu?

I'd like to continue running my XP Pro so I'd prefer to forget about 64bit.

Yes, the 880GT is a bit old. At 3.2GHz, maybe a GTX285 (16,462) or HD4890 (17,255)?

The HD4850 is a little bit better, but certainly a more modern replacement for the 8800GT. Tom's 3DMark06 benchmarks show the following:

8800GT 11,109
HD4850 11,749

My own benchmarks PII X4 940 @ 3.5GHz indicate 13,208 for a single HD4850 and 18,494 for Crossfire.

If your 8800GT went belly-up today (ie died) then the HD4850 would be a good replacement.

that cpu is a beast, get an hd4890

your current cpu is fine. there should be no cpu bottleneck.. you need to get at least 2 good video cards to have a cpu bottleneck for 90% of games.