I was one of the unfortunate users of the G5 dual (2.5 model from June 2004). For those researching why your G5 is freaking out: Essentially, when a G5 "bleeds out" (also referred to by some at Apple as "a bleeder"), it fries the motherboard. You will experience bizarre problems which will all seem software-related. Symptoms include: strange mouse behavior (short of finding mice poop on your pad), USB issues, failure to boot properly, failure to backup properly, and the huge indicator: the fans working overtime and occasionally screaming! In 2009 Apple agreed to repair this issue. It took quite a bit of research and documentation of other users who had repairs done free of charge. I took the computer in to an Apple store and in April 09, I received back a computer with entirely new guts. $1200 in repairs. Now, about 1 year and a half later, the machine is leaking out again. I am in the process of researching secondary bleedouts. Apple Customer Service - to their credit (so far) - seems to agree. I have been issued a new case ID number and sent photos of the bleed. The rep told me it is being passed up to an engineer and I will hear back next week. Fingers are crossed and I continue researching users who have suffered a secondary bleedout.