If you are using XP [pro is mine] then each drive can/default is allocating page memory. I liked it better with 98se as I had a [1] drive totally dedicated to page memory. however, it has been stated here that firefly loses mass memory during rendering (least think it was said in last few days). My largest render production was 895 frames animation (talking heads JUST LIKE TV [sorry news is on and trying to out talk it ;-D]) and on xppro with 512mem w/10g hd free; had to constantly (least 4 to 5 times) grab additional page mem whereas my 1gig mem xppro never gave error for same rendition on harddrive with 76g free. Go figure.... Each system can be so varied that it is frightening and difficult to pin down problems. Which is why my old machine is now my email, document, flash, presentation, etc. and my new machine only runs my 3d stuff.