Well higher than the G3s and 4s anyways. Back in 2007 when the Intels had been around for a year I was in the market for a newer Mac and was eying various PM G5s for a while looking at a replacement for my G4. Browsing through Craiglist at the time I remember seeing dozens of dead G5s people were trying to offload and most of these weren't the liquid cooled G5s, they were iMacs and air cooled PMs. I know the G5s ran way hotter than the G4s but were there any other reasons that their failure rate was significantly higher than earlier Macs? I don't think I've ever heard of a PM G4 dying.