Z800 woes: Should I be running the IZ3D drivers on Vista ?

[satchmo]

I'm trying to find a solution to get my z800 working again now I have a 9600GT card.

I have the latest IZ3d 1.1 drivers, also Emagin Labtool to initiate 3d on the Z800. Athlon 6400+ dual core , 9600Gt , win Xp sp2. I am using the basic shutter glass option in the IZ3d driver

I ask should I be running Vista, as I seem to have a weird frame rate bottle neck. With both Oblivian and WOW, my my S3D frame rate when not stressed tops out at exactly 37.5 fps. The L/R frame orientation stays locked and everything fine, but the moment my frame rate drops below 35 fps I immediately start getting the L/r out of sync and lose my 3D. The moment it comes up to 37.5 its solid again. Wandering around the dungeon in Oblivian my frame rate is dropping down to 20 or so, which doesn't make much sense seeing as I was getting flawless S3d with my old rig of Athlon 3800 single core and 7600gt and old Nvidea stero drivers..

The 37.5 seems to be an articficial ceiling. When I tried the Nvidea S3d glasses setting in Iz3d , though stereo didn't enable ( and with `vertical sync' switched off in WOW ) my frame rate shot to 200FPS....so I really expect I should be getting 100fps in S3d. Interestingly with the Nvidea S3d choice which doesn't work, when I have Verttical Sync on my ( non S3d ) frame rate drops to 75 FPS which of course is twice 37.5 fps. So there seems to be some bottle neck there.

So what I've proved so far is that I don't need 60 fps..they can hold sync at 37.5 but when my frame rate drops lower ..even slightly lower things go awry.

Can anyone explain whats happening and should I be running Vista, will that help?