It is not a powered liquid cooling system, it’s a passive heat pipe that runs through the massive heat sink.
looks like liquid cooling to me, as well as heatpipes that connect to a smaller heatsink. That’s just for the dual 2.5Ghz one, though. The others seem to have the heatpipe connected to a massive heatsink thing.
Liquid cooling does not a G5 make. Sure, you could build a G5 “compatible” if you could get all of the components. I know there are companies that make PPC motherboards. Whether they go up to the G5, I don’t know and won’t bother researching. But… there are other Motorola/IBM PPC machines that exist. They can’t run Mac OS X, though, because there’s other proprietary hardware on the motherboard.
Well, you could easily run Linux on these machines (well, that’s their intent; they’re Linux boxes). In which case you can run Mac OS X in a virtually full-speed virtual machine. But that’s against the Mac OS X license.
So, to build a Mac compatible machine, all you need is an official Apple motherboard. These are available. Not the same thing, though, as having a choice of 100 Athlon/Pentium boards available.
The rest of the parts – even liquid cooling – can be bought off the shelf. I think my last proprietary Mac was my Colour Classic bought in 1993. I want to say that my Quadra 636 had off the shelf everything else, except the video card. By time I moved to a Quadra 6400, even the video card was off the shelf. Hell, the 1.5GB in my PowerBook is NOT Apple memory – only the obtuse pay Apple prices. Similary the 0.75GB in the G4 are off the shelf, cheapest-of-the-cheap PriceWatch things. People says Macs are expensive. They’re NOT, if you’re smart about upgrading.
Well will you look at that. Jeez, you could be right. And here I thought if I asked the question on the MacNN boards, as well as in an Apple Store, and they all said “it’s soldered on the mobo” that it was, in fact, soldered on the mobo. Thanks so much for the link!