Help with graphics card problem

Hi,i'm new to overclocking but was able to successfully overclock my intel c2quad q8400 from 2.6 ghz to 3.2 ghz on an asus p5b deluxe mb with 4gb corsair2x2048-6400 memory with timings of 4-4-4-12 at 2.05v..I tested using prime 95 for over 12 hours with no errors!Now getting to my problem, before the cpu overclock my nvidia geforce 8800 gts graphics card was able to run crysis and other 3d intensive games with absolutely no gliches and was scoring about 15000 on 3dmark06. After the oc, crysis is running very slow and my 3dmark is under 5000. I dont really care about the mark score all i want is to try and get the system to run as good as or better than before!I have a 500 watt ps and a zalman cpu cooler which is keeping the cpu temps under 50c. Can someone please help?Thank you in advance!