Screen stuttering on dual monitor set-up

[yathink13]

Okay, so my rig is listed below:
Q9450 Oc'd to 3.2
4 gb of ram
4870 graphics card
asus rampage mobo
windows xp 32bit
some WD HD's (2 500gb)
Dell ultrasharp 24" monitor
LG 19" monitor

I've noticed that when I play anything game wise on the 24" (mostly warhammer online recently) and I play it in windowed mode, when I move to an application on the 19" monitor like vent or an open firefox browser i get ALOT of stuttering on the main monitor.

My question is if this is most likely because the 4870 can't handle the total screen real estate or if i have another problem somewhere.

 

[Katamarino]

I hope its not the power of the card; I'm planning to run 2 24" screens off of mine!

Have you checked that the display adapter in the game is set to the correct option out of 'primary' or 'secondary', and tha the window doesnt overhang onto the other monitor?

 

[yathink13]

I'm thinking it may be the card because in large keep sieges on warhammer i get some serious frame rate drop but we are talking about 50-60 people on screen at one time on a really large monitor with all the graphics turned to max and all sorts of special effects going off.

Maybe it's time to buy a second card and x-fire them.