Mike, you have just done considerable damage to my campaign to buy a Mac...

It's one of the few times when it makes sense to say 'it's the exception that proves the rule'. You see, nobody has met our problem before; everybody's suggestions for fixing it have been about third-party components - RAM, the graphics card, the SCSI card. We meet puzzled head scratching wherever we go. It is clear that our experience is, precisely, 'exceptional': evidently, macs just don't do this. So buy a G5 tomorrow, and relax.