This is a very weird problem, which I resolved but I still feel that you guys should know.
I was playing metro last light as well as assassins creed, the only 2 games i managed to play with my new PC. My spec is: http://speccy.piriform.com/results/MYWI5qzjsg8BIbXWrkUMeWw
I noticed a very weird graphical lag and it looks like as if my FPS is somewhat 1-3 FPS for about 1-2 seconds. But upon checking my real FPS, its 50 and not 1-3 fps.
I tried tweaking everything and nothing worked. What I did was disable the WIFI capability of my motherboard and the issue was resolved.
why is this so? whats with the WIFI that causes this problem? the problem DOES NOT occur when I am using a single GPU only when 2 or more GPU is utlized and the built in wifi is on.