Well, I'll jump into this:
If your motherboard has an embedded SATA controller, its worth it to go SATA rather than ATA100/133. Not per-se from the burst transfer speed, but more because modern SATA drives are 7200 RPM AND they have cache algorithms for read ahead and write back cache. Assuming your drives are defragged frequently, at least weekly, you WILL see a speed advantage. Defrag, anti virus, AND Everquest II are all sped up on my rig vs ATA100; I attribute this to a combination of disk drive caching algorithms and the better firmware support. SATA is full duplex for acknowledgement of controller commands; there is no potential for the bus to wake up in a lower speed if you have two drives on the same channel (in which case clocking on that IDE/ATAPI channel is according to the SLOWEST of the two drives), when either drive is not UDMA capable (this matters mostly for older CD_ROMs, not the later rewriteables.)
I was a benchmark engineer 5 years, a compatibility lab manager 5 years, a PCI bus engineer 3 years, and a network engineer 4 years. All in all, my preference at this time is for Hitachi (formerly IBM) SATA drives, either in SATA-II or SATA-I (it doesn't really matter, they auto-negotiate according to your motherboard controller). Hitachi SATA drives can be tweaked a little more than others with a downloadable utility.
Caveats and gotchas: Stock Win XP SP1 and earlier flat out won't see the SATA drive controller WITHOUT AN ADD-IN DRIVER at boot time. Instead, if you want to make the SATA drive your boot OS drive, boot the Win XP CD from the CD and press F6 when it prompts you if you have any "add in SCSI controllers". You sort-of do, from their driver perspective. You then get to insert a floppy disk with the "RAID" driver for your embedded SATA controller. Of course, you'll want to make that before hand. Your install can now proceed normally, you wont need the disk again. Or, boot with XP SP2 and skip that. Nice.
EQ 2 has a lot of files that can be read, especially sound .VPK files and textures for your zone. You'll see zone loading improvements, but you should defrag your hard disk every so often to optimize the value of read-ahead disk caching at the drive firmware. It makes a huge difference defragging and running Anti-Virus checking, to have the read-ahead enabled.
Flame if you like, but the issue isn't burst transfer, its caching, mechanical rotation latency, and OS driver support that makes the SATA controller a better way to go. My opinion.
- GS
Edited, Thu Jan 19 10:17:18 2006 by DobriyIvan