Also depends on your version of Vue and your operating system.

Vue 6 Pro Studio is a 32 bit application so it is limited to only 2 gig.

Windows XP or Vista 32 bit are limited to 3 gig at max but any single app is limited to 2 gig.

If you are going to get a system with 6 gig, you also need to get Vue Infinite and XP 64 or Vista 64 or a newer Mac since all of those are 64 bit.