I have 2 Western Digital MyBook HDDs and an OWC Firewire DVD-RW drive linked together, running on the Firewire 400 connection on my MBP. On one of the HDDs, I keep ripped copies of part of my DVD collection. I normally make a backup of my DVDs using this external burner and Toast 8. Some of my DVD rips will burn straight to the disc without compressing while others require compression (I have it set that compressed DVD files get transfered to my MBPs HD before burning and then deleted after burning, so the external burner is not taking data off the Mybook it shares a Firewire connection with). Whenever a DVD file requires no compression, it will burn straight to disc off data on the MyBook that the burner shares a connection with. Here is where I have problems. Toast seems to lock up after the DVD is only several % completed. Am I simply asking too much of a Firewire 400 connection? When I run the burner off of USB I have no issues. I like to use as many Firewire 400 devices as I can since I can daisy-chain them together and not take up precious few USB ports.