Just got a new Optiarc AD-7170 (Made in China Nov 2006 and 1.02 firmware but newer than Liggy's 1.02b...so perhaps 1.02c) and I'm having aweful burns with this. I've tried some Verbatim 8x DVD+/-R media that's been great with my other NEC drives and also some dubious TDK DVD+/-R 16x media (CMC-MAG).
My current config is with all drives using Cable Select:
PATA Primary Master = Hard Drive (UDMA-5)
PATA Primary Slave = LiteOn DVD-ROM (UDMA-2)
PATA Secondary Master = Optiarc DVD Writer (UDMA-4)
PATA Secondary Master = Plextor CD Writer (UDMA-2)
My chipset is a VIA KT400 and I'm was using the latest VIA Hyperion drivers 5.10. (I just updated to 5.11 so we'll see if that fixes anything.)
FWIW, I also had access to another AD-7170 (Made in Malaysia Sept 2006 and 1.02b firmware). It had similar problems so the likelihood of both being bad is doubtful.
So what is the key to getting good burns with this drive? I even tried forcing it to UDMA-2 in the BIOS but that didn't seem to change much.