I'm actually surprised this is also occuring on Apple's monitors as-well. I had this issue when I updated to OS 9.1 on my Beige G3/266 Desktop. I lost the 1152 X 870 Screen Resolution on my retail ATI Rage Orion PCI card (which I added in for running dual monitors). After the upgrade to 9.1 I could only get a "best" of 1024 X 768 on my ViewSonic E-771 17" monitor. This is my "better" monitor, my other one is an old Packard Bell 17" which can only get 1024 X 768 Max.
The only way I could fix the issue was to switch my ViewSonic back to the original monitor port, and put the PB on the rage card. I'd prefer the VS on the Rage, but maybe it's just a matter of a driver update from ATI.
I can't say I've seen the problem at work on Mac Systems with OEM Rage Cards (Blue and white G3's and a G4 server). Two such systems are also running 17" ViewSonic monitors. The rest of our real Graphics workstation systems run 22" Monitors and they were all "okay" with the 9.1 upgrade at a 1280 X 1024 Screen Resolution.
I've never even heard of a 1056 x 792 resolution before, it's not a huge difference from a standard 1024 X 768.
Mike
[This message has been edited by MikeM32 (edited 01-28-2001).]