I'm running V4 and on my previous machine, a P4 1.8 gHz with a M-Audio Delta 66 I ran into the same thing at around 30 tracks and 250-300 takes. I always started a submix to get further along. With a P4 3.2 gHz and a Layla 24 no problem. I've been to 48 tracks and recorded with no hiccups. From your posts I've seen, I doubt if computer speed or marginal sound cards can account for your situation, but my problem seemed to be (mainly) the Delta card.