right now the PATA drives are on the normal motherboard IDE connectors, and the SATA drive is on the built-in SATA controller on the motherboard as well.

Good point about observing memory usage. I have a feeling I won't have to worry about that. The task manager, at least, doesn't show that much is in use when I'm converting using TMPGEnc. I certainly have a lot of headroom in that area.