Thinking bout upgrading my XFX 6600GT AGP card. Now that i have an Opteron 144 and EPOX 9NDA3J MB does it pay to upgrade my GPU? I can sell my card on EBAY and probably get @ $100 so could spend @ $200 total. Will I see significant changes or should I just save my $$. Mostly play BF2, UT2004, FEAR etc