Game speed says 100%, but game runs slow.

[Otakumegane]

So after popping in Sin & Punishment 2, I noticed that I was getting some pretty bad slowdown, but when I checked the gamespeed it stated 100% speed.

I brought everything down to minimum settings and it was fine but I don't believe it was my GPU considering I only had it at 2x res.

[skid]

I've seen V-sync cause this effect as well as the VBeam speed hack. Maybe try turning both of those options off.