I have a PowerPC G5, I just installed Ubuntu Mate 16.01. I have Geforce 6600 (card). The top portion of the screen is cut off about 1/4 inch. The mouse does move into that area (although it's cut off and there is room for it. It is not cut off by the limits of the screen. It looks like the displayed area is smaller pixel-wise) and I can click the power option button on the top status bar even though I cannot see it. My monitor is a Gateway LE1936 (FPD1976W)
Standard options except more memory and larger hard drive.
1440x900 native and Ubuntu Mate is set to this. I tried all the video settings such as vertical refresh rate, resolution, etc... I know this is out of LTS, but hoping someone had a similar problem.