[newbie] Video problems

[JK]

I am running a number nine I128 with four megs of ram. my monitors hsync is
30-95 and vsync is 47-150
res is 1600x1200 max

When I was running RH 6.0 it could handle 1280x1024 at 24 bpp now I am trying
to set my monitor to the same res and depth, but it will only hit max of
1280x1024 at 8 bpp....

Any help on what I can do to fix that little problem? I am using mandrake 6.0

TIA

John K.