120Hz monitor question

I've tried googling around for answers to this, but couldn't find anything useful. Figured I'd try posting a few places.

I'm looking at getting a 120Hz monitor (probably the Samsung 2233RZ) to use in a dual monitor setup. Right now I have an Asus VW246H (not 120Hz) as my main monitor, which I'd shift over to use as my secondary.

Will I have any trouble getting the 120 Hz out of the monitor if I've got a dual monitor setup with 2 monitors that don't have the same refresh rate? I have heard from a couple people that there were problems with this in the past with XP.

I'm running 64 Bit Win 7 Pro with a 4890

Thanks