so, this is my first post here after spending a decent time lurking and im hoping to get some light shed on my issue ive been having with my 1.1 mac pro. machine specs...1tb HD with OS 10.6.8 on it, 8gb of ram from TransIntl, ATI x1900 GPU, x5355 CPU's. i was having an issue with the pro locking up on me during normal use, sometimes just surfing the wed in safari and listening to itunes, the screen would lock up...but itunes would still play in the background or say a youtube video etc. power down, reboot, everyhting would fire back up. friend thought it may be ram related, when this first started happening i only had the measly 2gb of apple supplied ram the machine came with back on 2006. so 8gb was put it. problem happened less, but still happened. thats when the x5355's went it, i wanted something that would render video faster anyway at the time and a new machine just wasnt in the cards so the CPU's upgrade was the logical step. the machine no longer locked up doing random everyday tasks, but now only froze if i was jumping back and forth from FCP X and Motion 5. cranked the fans in SMC fan control, and had no more issues thus far. the other day an issue came about, i was downloading a file walked away and came back 20 minutes later and the screen was frozen, cursor still moved around but screen was frozen. the file said on the screen that it downloaded 1.2gb of a 4.3gb file, rebooted the computer...started the download client again...and it instantly said that it downloaded 3.4gb of the 4.3gb file. this makes me think that the computer is still working, even after the screen hasa frozen and become un useable. would a failing GPU be to blame? im out of ideas, and i was looking for an excuse to upgrade to an ATI 5770 with FCP X anyway, i just want to FIX my issue at hand before dumping any more "play" money into the machine.