Me and a friends both have similar spec gaming pc's, both home built with lots of research gone into them. Now the issue is that my friends pc is running the same games on highest settings with high fps, where as mine on highest settings is lagging. My specs are 1st gen i7 920, asus p6t deluxe v2, Zotac Nvidia gtx560, 3x2 6gb OCZ Blade 2000mhz cas-7, coolermaster 800watt power supply on windows 7 64bit. Both mine and my friends computer were built to the same value except his 2 years newer than mine and 2nd intel processor on a i5 overclocked. Why is there such a performance difference?
Also i still have an absolutely terriblely old hard drive will that cause an issue?
Thirdly recently I have been getting blue screen with memory check popping up about 4 times last month?
What concerns me is the memory and BSOD. Any more details on what the BSOD says? Bugcheck codes etc?
If you want to test the memory you can use MemTest - http://www.memtest.org/#downiso
You will have to download the iso and burn it to a disk using something like ImgBurn or Nero etc
Also, are you using the latest drivers for your graphics card? Get them from the Nvidia/Ati website.