I have an obscure problem.

I want 1152x864, but the current liveCDs limit me to 75 Hz, which flickers. I can get 85 Hz at higher and lower resolutions.

This affects both of my machines, using the same monitor. Neither machine uses a proprietary driver. All liveCDs correctly identify the monitor.

My Ubuntu 10.04 LTS install has no problem with 1152x864 at 85 Hz, and will even allow 100 Hz.

My Lubuntu 12.04 install on the other box has the same problem as the liveCDs.

I've also tried the Scientific Linux 6.3 liveCD, which is kernel 2.6.32-x like 10.04, instead of the new 3.x kernel. Still the same problem with 1152x864.

I'm stuck. Can't figure which way to come at the problem next, or what might be the root.