I used PCSX2 couple years back and everything was great. Now I have two PCs and am getting the same results on both of them. Every couple of seconds the FPS go down to about 30 and then back of to 60. The sound and picture and everything slows down.

PC1:
OS: Windows 7 Ultimate x64
CPU: Intel Core i7 - 2600k (3.4 GHz)
RAM: 16 gigs
GPU: 2x GTX 460 in SLI

PC2:
OS: Windows 7 Professional x64
CPU: Intel Core 2 Extreme Q6850 (3.0 GHz)
RAM: 8 gigs
GPU: single GTX 460


I thought it could be the video card, since those are the only two things they have in common, but I even tried setting the graphics plugin to GSNull and I could still hear the sound stuttering.

Any ideas as to what could be causing this?