Funny those computers cost LOT lot of money. Even though they are eclipsed power and capacity wise many times over. How many of you think that your 2011 imac will have processor upgrades available and keep running smoothly in 2021? OR just end in a puff of smoke and a burnt ciircuit board? My uncle gave me that G4 400 and he already went through one iMac that burned up the power supply and then the finally the whole board, shortly after insurance expired. They don't make them like they used to!
I don't care much for the imac design. It just traps a lot of heat and provides little room for expansion or for hooking up externals. But I got one because it's affordable!
I found out, not on the internet, but from a repair shop, where my uncle bought a new 2007 aluminum iMac, that the G5's that I always drooled over, especially the later model dual core, faster Power PC versions, had a huge number of cooling fans and a water/fluid cooled design that failed more often than not, taking some, very expensive to replace parts, out as the coolant puddled. The latter G5s came with an absorbent pad on the bottom to collect the leaking fluid, before one of the main boards shorted in a liquid bath, should the owner miss the tell tale first drip marks. Not exactly the the best fix one would expect for a top of the line Apple...
Apparently those leaking G5s were responsible for keeping the repair shops quite busy and were sorely missed as the intel processors showed better thermal characteristics even with more power and of course NO NEED FOR LIQUID COOLING SCHEMES. I am not sure what percentage of the liquid cooled G5s failed but I suspect it will be most of them because the same material used for sealing the system. At least that's what I remember. Yet I never heard about the leaking G5s anywhere on the internet, or Mac newsgroups. But a a Mac shop. Seems like kinda of a big screw up to get missed?
My year 2000 G4 just kept accepting more expensive upgrades, even as the price probably stayed less than $100 and it keeps on running although some applications and the later itunes would slow it down, even though I upgraded the processor from a 400mhz single to a 1.5mhz single with an OWC kit and maxed the RAM. Replacing a video card fan and just adding more air movement with another carefully aimed accessory fan I sure hoped has helped for the the extra noise created.
I believe the most important fan, is one I mounted at the top rear just outside the existing fan, to help move hot air completely out of the case. Especially useful during hot days when the room gets very warm. I suspect that one fan gets overlooked and as you can only cool off only so much blowing the same hot internal air over the interior boards!
No problems, but I have religiously increased air flow, both to internal components like the video card and processor and air movement with any upgrades after hearing so many stories of Power PC macs burning up after upgrading to more powerful aftermarket processors.