It is a good time to buy single threaded application Mobo's. An incredible mobo for GS3 is the Supermicro P4SCT+II w/ an engineering sample CPU. Like the Intel P4 3.4GHz Northwood thats currently on ebay. You can overclock that combo up to 3.9Ghz @ 233!! Thats pushing it though. It will run very stable @ 3.7Ghz. The onboard RAID is custom SATA that is designed to run w/ Raptors in a RAID 5 config. This board never became very popular because it was the 1st Mobo designed w/ the upgraded 875 chipset. It is the most mature P4 combo, and when OC'd to 3.7 is on par w/ AMD FX 57 benchmarks. But Intel is the most stable chipset for audio at that speed IMHO. If you are sick like me, here is a dangerously fast GS3 rig built to smoke 'em live.
Intel P4 3.4GHz Northwood ES w/ unlocked multiplier
Kingston PC3200 DDR ECC 2 GB
WD1500X x 2 ( 3rd generation Raptors w/16 MB cache,10k rpm )
WD360G x 2
Run the drives in a 3Ware SATA RAID cage using dual RAID 1 for redundancy, or buy the Zero RAID card for the RAID 5 assembly.