Display shakes when running Samsung 2233rz at 120hz

[kakarot27]

i recently got the samsung 2233rz 120hz monitor, and whenever i set it to 120hz at 32bit colour the screen shakes. but when i set it to 16bit colour its fine. at 60hz it is fine either way.
i am running a 4850
connected with dvi
latest drivers
overdrive/clock is turned off
any ideas on how to fix this? and thanks in advance

 

[Tmagic650]

The computer's video processor probably only runs at 72Hz max

 

[kakarot27]

recently ati released their 10.5 drivers for the 4000 series cards to fix the problem. and it works now at 32bit 120hz