with my aiw 128, I could choose different levels of compression and quality to tailor the bitrate on recordings. I can't actually remember what specific numbers were (been a while), but I do recall that when recording using the highest quality level, I'd loose lots of frames when recording to my ata33 drive, but none when saving to my lvd drive.
now, that could have been issue with my rig, but I remember the quality of the capture was very nice and I've read that the rage theater chip on the aiw pros and radeons are supposed to do an even better job.
BB