digital fracturing of record files

[Dain]

I'm bouncing a 20 minute piece with at most 4 simultaneous tracks and several effects. This has severely taxed my BW G3 350 w/ 512 of ram and ATA drives. So much so that i ended up dividing the song in half to record in two pieces which seemed to work. However, now after successfully exporting the first half everything that gets recorded is severely distorted digital chunks. Now, in fact even previously ok songs won't bounce without this horrible fracturing!