Using video memory for virtual desktops?
 

I like to keep a lot of applications/windows open so I make fairly heavy use of virtual desktops. Now when I switch to a different desktop (with, for example, 3 firefox windows) I first have to wait before all screens are repainted. Why is this? I'm using a 1920x1440x24 desktop which is approx 8MB. With 4 virtual desktops that's only 32 of the 128MB that my Nvidia FX 5700 has.

Is it possible to keep all virtual desktops in video memory so switching to a different desktop can be instant? Currently I don't have to wait _that_ long before everything is repainted, it's one second max, but it's still annoying and seems to be very unnecessary...

BTW I'm using Debian Sarge with XFree86 4.3.0.1 with the binary Nvidia drivers.

No ideas?