Hello, I just recently acquired this mighty powermac as a final replacement for my long obsolete but still loved dual 1.42ghz MDD G4. Like many here I grew up on macs at school, my original was a smurftower G3 that I had maxed out cpu/gpu/storage.ram and used as a file server for many years. I have to say that there are many surprises with the Quad G5 that I was not expecting. Heat My main computers for the past five years had been self built PC workstations machines, and I am not sure if is due to a long history with monolithic top of the line GPUs but; the Quad G5 is not the power hog nor heat maker people made it out to be. Even back when it was made there already were Dual socket SLI setups that could shame it by kill-o-watt and as an electrical furnace. It hardly kicks out any more head under load than a single core pentium 4 or K8 with a 7800GTX from way back did. I think this is due to having a very advanced digital power phase. Either way an early FB-DIMM(!)quad, Octo or Hexa Core Mac Pro with low end graphics should have no issue whipping the meter in ways the Quad Core G5 could only dream of. It could be that dual core G5 processors from stepping improvements or whatnot were a lot better than Apple rightfully assumed after the AGP G5 debacle, certainly not where Apple wanted, but not the thermal nightmares they were before. Liquid Cooling was likely kept due to keep noise down and because Heat Pipe coolers had not yet reached the high efficiency of the last five years. My Quad Core G5 with a 7800GTX is simply no match for my Nehelem based i7 with a 580GTX when it comes to heating this room, both are hungry big ol workstations, but the Quad G5 under load can't match an i7 and Nvidia Fermi. But this brings me to my second surprise Performance I saw the writing on the wall for PPC during that Keynote long ago; when Tiger was loaded onto an Pentium 4. The Mac Pro was too much of a financial pill when I was a student. All these years later this Quad G5 was bought entirely to use my old pile of PPC disk, some are not so old, UB infact, and were gifted to my from colleges who are now on the next literation on Lion. I have to say even with its limitations on many older applications, but G5 is a much more pleasant to use at times than my Nehelem PC. Both computers are blazing fast in general use due to their 240GB SSD (Sanforce naturally on the G5) and 16 and 18GB of ram; but when something is poorly done in an application, the Quad G5 seems to process its way out quicker. Not saying anything as mad as the Core i7 is slower, it is likely Windows 7 fault; but for whatever reason the Quad G5 is still a powerful system half a decade later and can easily hold its head high among the Quad Core systems of today in intensive task. Many speak of PPC in terms that do not outline their obsoleteness by software cut off, but by more that they are uselessly slow next to modern processors. I'm just saying no, it only became so due to corporate maneuvering, not architectural limpness. Had Apple continued to use PPC, IBM could have easily ramped up the performance to go head to head with the best Core 2 did and beyond; but like many things there was allot more to the decision than what makes the best guts for workstations. Cost, Mobility and Standardization is how you run a company and so the G5 died. I was surprised by all this, am surprised that for the past month I have almost completely transfered my workload to this machine. I have always loved OSX, just didn't expect it to have the speed for me to be happy doing heavy work upon it. I acquired it more for limited and nostalgic stuff, but thanks to its power and endearment of not being saddled with Windows 7; for a few years this will likely be my main center of operation. Plenty of time for Apple to jump architecture to ARM or who knows what.