Burner lockups (px716sa & 4166B)

A few months ago I rebuilt my pc to a dual core opteron system, with a asrock 939dual-sata2 motherboard. Right after my Plextor 716SA started locking up during burns, it started by locking up right at 99% when using the boards ULI based sata ports, so I switched to the boards addon sata2 port and things worked better but still locked up, but very randomly. Per the advise in the plextor forums I bought another burner as it was mentioned my board most likely didn’t support the 716SA properly, as such I bought a 4166B and all seemed well til it too locked up at 99% same as the plextor did. This has led me to believe either the motherboard is bad itself or perhaps the Fortron 550-PLG-SLI power supply I bought during my upgrade is to blame. I have updated the bios/drivers to the latest of everything and still the problem persists. Before I throw anymore money at this system (Might just sell most of it off and rebuild with a new Intel Core proc this summer) I wanted some advise.