Although i have been building my systems for a few years...this is the first time i decided to o/c my cpu. This is my h/w:

e6420
2gb ddr2-800 5-5-5-18
965p-ds3 gigabyte
8800gts 640mb

latest drivers all around inlcuding latest released nvidia driver, and winxp pro sp2 all updates installed.

I have been running my system for a few weeks without overclocking just to make sure it was stable. Today i have made the necessary changes on the bios, thanks to the nice o/c guides here, and i have put my cpu at 3.2ghz with fsb at 404mhz. Everything looked fine and the system boot with no issues including running for about 1 hour prime95 in both cores simultaneously. The only other change i have done was upped the cpu volt @ 1.4v, fixed the pci-e frequency at 100mhz and set the memory multiplier at 2. So far so good:

As i was benchmarking again the game that i'm playing now (Armed Assault) i have noticed that the fps had dropped significanlty (from 38avg on the benchmark to 25fps). I run 3dmark06 and the demo games on that were crawling with a total score of 4005. Gfx card had been overclocked before @ 600/900. Monitoring temps, cpu load etc it became apparent to me that the gfx card was not working at its potential, since every time i was running a game or graphics benchmark temperature was hardly raising, indicating that somehow the gfx card was not "engaging".

I went back in bios and changed the following 3:

Pci-express @ 102mhz,
MCH volt +0.1
Init display device from PCI to PEG.

After i reboot all the benchmarks were fine. New score in 3dmark was 10430, game benchmark was up to 44 and temperature of the gpu was coming up when it was working.

In all occassions i have run cpu-z to make sure that the changes in o/c were registered.

Although the issue looks like is resolved, i'm confused as to why the gfx card will not "engage" on the first instance. Is it something that happens often?

thanks