Sonic Riders ZG help

[Xx2TailsxX]

Hi, so I just got Sonic Riders ZG for the PCSX and I'm not sure what the issue is, but it lags sometimes (I mean like every 10 seconds) And when I use R1 to dash, the screen turns grey until the dash fully starts. Anyone have an idea how to fix that?

Computer specs are

AMD A8-3820 Quadcore @ 2.5 GHz

Nvidia Geforce GTX 560

12Gigs AMD Performance RAM @ 1600MHz

Win7 Pro x64

Thanks ahead of time!