Maybe your AMD Radeon HD 6630M. Altho I run PS2 in highest settings and its not great fps my specs are:
Phenom II x4 965BE overclocked to 3.8ghz
8gb Kinston Hyper Blue 1600mhz
XFX 7750 1GB DDR5 oc'd to 850mhz
Thermatake TR2 600w psu
Windows 7 64bit
Due to the amount going on in PS2 its a heavy game, at least on my system.