Anybody running mixed RAM in their early '08 8 core Mac Pro? I was just checking macsales.com and the RAM prices for my machine are crazy compared to the '09 and '10 versions. I don't mind getting the less expensive RAM (DDR3 PC3-10600 ECC 1333MHZ) if it will work in my system, even if it downclocks to 800Mhz. My concern is DDR2 mixed with DDR3. I currently have 8 gigs (8x1Gb) and would like to up it to 14 gigs (6x1Gb & 2x4Gb). Any suggestions?