I have a 2006 mac pro 1,1 with an xserve raid attached running OSX 10.4 server. (funny side stories: I recently had a problem with the xserve raid (bad raid controller) and when I called apple tech support, they actually said "what's that?" I bought the xserve almost 10 years ago - it has a 7TB capacity, and it cost me ***$11,000***!) since the xserve is becoming glitchy, and since you can buy 4TB single drives for $200 now, I'm thinking of decommissioning the RAID and instead loading up the mac pro with drives. my questions are: I see info that suggests that the drive capacity limit for 2006 mac pros is 500gb each, but I also see info that that's just old info and not true. is it actually the case that there is NOT a limit? will there be any issue running current drives, which are sata3 on the sata2 bus? I mean apart from speed, is there any reason the drives wont work, or that it will damage the machine in some way? is there any reason I should upgrade from 10.4 to something more current? all it needs to do it sit in the corner and share files - I'm not hosting a website, or doing any VPN, or running a calendar server, etc. if I DO look to upgrade, it seems I will need to upgrade to 10.6 first, and then I can upgrade to 10.9. with 10.9, it seems you can now just get the "server" bit of the OS as an add on to the regular version, so do I need the 10.6 server version, or could I do 10.6 (which I already have a disk for) and then 10.9, and then the 10.9 server add on?