Hello, I have an older system that I bought a gpu to bring it up to date, the motherboard is an abit is7 v1.2 and intel Pentium 4 overclocked to 3.5ghz with 2gb ram at 400mhz. I purchased a zotac gt 610 for regular pci slot since I had no pci-e slots on this ancient motherboard, The problem is while playing games on it the fps is all over the place playing world of warcraft on lowest settings it sits around 40 fps and spikes up to 70 and as low as 10 even without much action going on and just standing in the same area in game in fluctuates everywhere, So I'm assuming something is causing a bottleneck whether it's the pci bus, Fsb, southbridge, cpu(sits at around 90% usage), I have no clue.... so how would I go about diagnosing this issue and what if anything can I try to remedy this situation?