I have an a7n8x deluxe myself and the reason I would like to use an SATA DVD burner is that I could then put in another IDE hard drive. A question that I have is that can I boot off of the Plextor 716sa?
The Silicon Image Sil 3112 SATA controller on this motherboard uses the PCI bus while the IDE controllers bypass it completely.
In my current setup, I have three IDE hard drives and a 4x IDE DVD burner. Of the three IDE hard drives, two are attached to parallel-to-serial ATA converters so that each device is hooked up to its own controller by itself. No master/slave configuration of any sort.
The sustained transfer rates of my three hard drives are around 60MB/s with the peak rate at 100MB/s (UltraDMA 5). Reading or writing to both of these at the same time will have the potential for saturating the shared PCI bus. My 4x IDE burner burns at a rate of 5500 kB/s and have a peak transfer rate of 33MB/s (UltraDMA 3) which is much slower than the hard drives.
The 16x Plextor will presumably burn at about 22MB/s but will also be slower than the hard drives.
This is, ofcourse, totally meaningless for the newer generations of motherboards on which the SATA controllers also bypass the PCI bus. Also, the whole point of PCI Express is that the sort of sharing I've described is almost completely eliminated except for any legacy PCI slots.
This sort of thing CAN be become part of an argument for upgrading your PC but there is a legitmate point for wanting an SATA DVD burner.