Well, I don't know about monitor drivers (didn't think monitors used drivers?), but perhaps the refresh frequencies are set up wrong? Can you see any warnings in the Xorg.0.log (or perhaps XFree86.0.log or something similar)?
You can try to search google or monitorworld
for you monitor specs and put them in the monitor section of your config file. Here is the part from my file:
HorizSync 30.0 - 65.0
VertRefresh 50.0 - 75.0
Change the 'HorizSync' and 'VertRefresh' to equal the specs you find for your monitor.
Hope it helps!