This is my first post here, and I'm writing at the suggestion of Plextor's technical support. I called them originally because of trouble installing a PX-716A in a new server. The PX-716SA would show up in the BIOS of my Tyan K8SD Pro, but no CD/DVD drive would appear in Windows Server 2003 x64. They had no suggestions other than to check for help here. I looked here briefly but found nothing like my setup.
After working with the system for a while, I solved the problem myself. I'm just writing to let others know what I did in case they find themselves in a similar situation.
Essentially, the problem was that Windows Server 2003 x64 did not have drivers for the motherboad's Silicon Image SiI 3115 SATA controller so it could not interact with the PX-716SA. The retail motherboard did not ship with drivers for the SATA controller, but x64-compatible drivers are available online at Silicon Image's site. After installing these and restarting the system, the drive showed up and read cds and dvds well. I have not tested recording on it yet, but I would presume recording would work well with appropriate software.
One note regarding the drivers: SI offers both RAID and IDE drivers for this particular SATA controller. I chose the IDE drivers first because doing so made more logical sense to me than installing RAID drivers for an optical drive, but I can't comment as to whether the RAID drivers would work. I can only report that SI's IDE driver for the PX-716SA worked for me.
So here's my set-up:
Motherboard: Tyan Thunder K8SD Pro (S2882G3NR-D)
Processor(s): 1x AMD Opteron 242
Memory: 2x Viking ECC Registered DDR 1GB PC-2700 modules
RAID Adapter: MegaRAID SCSI 320-2 Dual-Channel Ultra320 RAID Storage Adapter
Hard Drives: 3x Hitachi Ultrastar 10K 36GB Ultra320 SCA Drives (08K2477) in RAID 5 configuration (plan to add more later)
Case: SuperMicro SC742S-420 Chassis
Optical: Plextor PX716-SA
Hope this helps anyone else experiencing similar problems,