Is this the only SCSI card that works?
ATTO Technology Express PCI UL5D Dual-Channel Ultra-320 SCSI Host Adapter PCI-Express Card - Mac/Win (http://www.bhphotovideo.com/c/product/411310-REG/ATTO_Technology_EPCIUL5D0R0_Express_PCI_Dual_Channel_UL5D.html)

I have some older Avid 10K drives that I want to Boot OSX from them. Then the OS will run faster (I have with Stripe 0). Yet this ATTO card is $500.00!

Thoughts?
-C

If you want your OS to respond better then use a 10,000rpm Raptor as your boot drive. Having your OS live on an external drive is disaster waiting to happen, not to mention that you'll really not see any speed increase by putting the OS on an external in fact, you'll slow it down considerably. The reason is because your forcing all the core files to be moved through an external bus which first has to make it past all the internal API's and memory paths on the motherboard.

If you want an external SCSI array however, the UL5D is the perfect choice.