the HDD and DVD were on two separate channels, each the master. I went ahead and put the DVD back on the MB controller, but it now performs slightly worse on the benchmark, and the newly tested burns also do not boot...

I'm not desperate enough to go cross-flashing firmware just yet.

Considering the benchmark performance, is it safe to assume my earlier proposal, that a disc will burn successfully (with errors) and the OS can do reliable error correction; but as a boot-disc it is not suitable? Just want to make sure I should be focusing on hardware. I guess considering how many different apps I've burned with by now, it MUST be the burner.