Eagler:
The ATI control panel has options as to how to handle to refresh rates in XP. (It used to be that you were just stuck with 60 Hz (yuck).) I can't recall the exact details now, but if you go into the display advanced properties, look on the display or monitor tab. Somewhere in there is a setting for refresh rate override. There are several options, which can be specified individually for various resolutions or in a global manner. One option is to set a fixed refresh rate for a given resolution, e.g., to set 75 Hz for 1280x1024. It sounds like this may be how yours is set up. Another option is to specify that the card should use the desktop refresh rate (in your case 90 Hz), but in my experience this doesn't always work. I have gone in and hardcoded the refresh rates to my monitor's max for all resolutions, and I haven't had a problem yet.
As far as I know, your AA and AF settings have nothing to do with the monitor refresh rate, and you should definitely be able to hit 85 FPS with your setup at 1280x1024, even with AA and AF maxed (6x and 16x, respectively). I would suggest that you try 1600x1200, even if that means cutting back on AA and AF. I find 16x12 to be MUCH better than even the next lower setting, with or without AA and AF.
Just my $0.02,
JNOV
