4 GB is a must have - i think. i'm running 5x wow on a

- Q6600@3,2Ghz
- 8800 GTS 512mb
- 4 GB / 800Mhz - Vista 64

4x wow installed on one HDD with minimum addons and 640x512 resolution @19" - no sound, low gfx settings and in keyclone FPS capped by 30
1x wow installed on another HDD, normal addons, 1920x1200 res @24" sound and good gfx settings.

it works very well =)
3-3,5 GB in use with all this wow windows open
sorry 4 my bad english =(

/tenta