I have the following PC:
Intel Core 2 Duo E6750 CPU
Gigabyte GA-P35-DS3P Motherboard
Evga 8800 GTS 320 MB
Patriot Extreme (4x1GB) DDR2-800 PC2-6400 RAM
I recently overclocked my CPU from 2.66 GHz to 3.2. In the BIOS I changed the "CPU Host Frequency" to 400 (from 333), the "CPU Clock Ratio" remained unchanged at 8x. I changed the "PCI Express Frequency" to 100 (from Auto) and the "System Memory Multiplier" to 2 to keep the memory running at 800 and giving me a 1:1 ratio between CPU and RAM.
MemTest worked with no errors. CPU-z and Rightmark CPU Clock Utility both showed 3.2 GHz. I ran Prime95 for over an hours and did not experience any error and temperatures were 50 C for the CPU and 55 C for both CORES.
But when I ran PCMARK05, my score didn't change much. And when I ran 3DMARK05 my score went from 14912 (prior to CPU overclock) to 6982 and PCMARK06 went from 8634 to 3856.
What did I do wrong? Why are my 3DMARK scores going down. I used the Company of Heroes performance test and confimed my average frames per second decrease from about 40 to 30 with the same setting.