lately i've been playing around with various tweaks on my two main windows vista computers.  one has 4 gb of ram and the other has 2 gb of ram.  on both computers i ran without a pagefile for a while and the 2 gb system occasionally popped up the system running low on memory message - i disabled the aero theme and that solved the low memory messages.  before deciding to disable aero, i cut back on the amount of background applications i had open (windows live mesh and the microsoft enterprise desktop virtualization betas both startup by default even when i'm not logged in/using them actively), but i finally decided on disabling aero since i'm using these betas on a regular basis.  on the system with 2 gb of ram i'm going to try readyboost (the ability to set aside a portion or all of the storage capacity on a usb thumbnail drive to boost system performance).  on the 4 gb system everything was running great - except that i couldn't see the final gigabyte of ram.  so i've since upgraded that computer to the 64 bit version of windows vista enterprise.  the 64 bit runs great and sees the final bit of memory so that i have all 4 gb of memory is available.  i will no doubt appreciate that with virtual pc.  the windows performance toolkit is another utility that can assist in the performance tweaking of the operating system - check it out.