I'm going to get the 20008 2.8 8-core mac pro w/750 gb WD as primary boot and the Samsung spinpoint 500 gb for data. I'll use the stock drive for saving backup (I'm not that concerned if I lose photos). For maximum photoshop speed/efficiency, is it smarter to go w/ 12 gb of RAM or 8 gb RAM and a WD 150 gb 10k RPM as a scratch disk? Thanks in advance!!!