Well, THAT was fun. Uninstalled the IAA, reinstalled the mobo's chipset drivers, rebooted 52 dozen times, re-enabled the RAID, reinstalled the RAID drivers, reboot a few more times...and: Everything works. Even SmartBurn.
So I can't burn at 48x w/o errors: oh well, I can at 40x. Good enought I guess, but kind of frustrating, ya know?
Thanks for help guys! Yet another reason CDRLabs is my home page...
Edit:
IAA is a must apparently; with out it it slowed way down at 30% and took over 6 minutes to finish (at 48x!). Still got that slow-down/errors at the end of the disc with it, though. Guess I need the 52x drive to burn at 48x.