My (PAL) version works fine (i have same processor, AMD Phenom 9950, Black Edit. 2,6Ghz) and it's usually at 100% and 99%, sometimes might goes down to 95% at minimum.
I use GSdz 883 (MSVC 15.00, SSE2) 0.1.13 one with the config looking like this:
Dunno if it's any help for ya (i'm using Vista also). I haven't had any large problems so far (except at Kilika screen went black after a cutscene).
I play thou with unlimited frame atm, so i don't need to wait all the stuff xP but that makes the sound not match the video (in cutscenes).
For sound i'am using P.E.OpS. SPU2 1.9.0
EDIT: I have nVIDIA GF 9800 GTX+
I use GSdz 883 (MSVC 15.00, SSE2) 0.1.13 one with the config looking like this:

Dunno if it's any help for ya (i'm using Vista also). I haven't had any large problems so far (except at Kilika screen went black after a cutscene).
I play thou with unlimited frame atm, so i don't need to wait all the stuff xP but that makes the sound not match the video (in cutscenes).
For sound i'am using P.E.OpS. SPU2 1.9.0
EDIT: I have nVIDIA GF 9800 GTX+