With the add-on cards, the motherboard's BIOS has no control over the DMA settings, only the BIOS on the cards can control that. I can't say I've done extensive tests on the Silicon Image- and ITE-based cards, but there is someone by the name of "engine" that had also dealt add-on cards.
I've had no luck with ITE 8212F RAID and non-RAID add-on cards at all, but engine had some luck with them, as he was able to use an "intermediate" ATAPI BIOS to recognize some optical drives. However, he couldn't achieve the 24-MB/s burst rate on UDMA-2 drives like BenQ or NEC. My tests with ITE-based cards were unfruitful, the cards (bought from CUSA) never worked properly as they caused hang-ups on my setup: Windows XP Pro had a hard time configuring and booting up. Secondly, the FLASH chips on the ITE cards weren't reprogrammable, thus, I couldn't test other BIOS versions.
Thus, I tried the Silicon Image-based card, which worked perfectly with LiteOn and BenQ (DQ60 & 1670) because they were all UDMA-4 drives. The LG 4163B identified and showed UDMA-2 support, but errored out whenever 16x burn was attempted. The BenQ (1655 and 1640), NEC (4550 and 3500), and AOpen drives were identified correctly by the Silicon Image chipset, however, they only operated in Multiword DMA mode. Even with SiI's own RAID software, UDMA-2 mode wasn't even listed as a selectable option.
Another attempt was done using Promise's UltraTX2 controller card with the latest BIOS. That resulted in an infinite loop of rebooting the computer if it sensed any optical drives connected to it, yet the computer booted up perfectly with no optical drives connected. Go figure.
So if you attempt to put various BenQ 165x and 1640 drives on the cards, you will NOT achieve UDMA-2 transfer rate. Only way is to use the on-board IDE controller, as that's how I'm using them now.
Here are two threads:
IT8212F flash update problem
Add-on PCI to IDE card won't DMA