iMac G5 Fan Modification

My father has an iMac G5, and these machines are notorious for emitting horrible high pitched noises caused by the CPU fan, and his was no different. Since I was there for XMas I decided to work with him to modify it to use a different fan. I followed the basic premise found here. The major difference was there was NOT a CPU fan hookup on the motherboard in his G5(Trust me I looked and unplugged everything ;) So instead we ripped out the CPU fan, cut the wires, found the 2 with the biggest voltage difference, and used that for the new fan. Also we were able to completely get the heatsink cover off, although I suspect this was because we got rid of the entire fan assembly.

The only issue was that the lines for cutting were drawn too large and we ended up with a slightly larger hole than it should have been(About a millimeter off). Also I tried one of those new-fangled liquid bearing fans. I used a 1200 RPM one, which isn't completely inaudible, but definitely less noisy than similar ones I have.

Anywho, pics or it didn't happen:



Also a side rant against Apple. First it was impossible(Yes I said impossible!) to figure out fan speed or system heat in software. Nothing was for his version of OSX(10.39 AKA: Hello Kitty) and as far I can tell there is no basic BIOS to look at. Also I couldn't find it in /proc. On the hardware side, the original CPU fan design was utterly retarded. It pushed air through a sealed up copper heatsink. This wouldn't be bad, except that the area the fan blows out is incredibly small(About 1/3 the size of a normal CPU fan). This obviously means the fan has insanely high RPMs and thus an insane amount of high pitched noise. I realize they wanted a slim form factor to look 'stylish' but did they fail to test the thing? They could easily have used multiple fans, or bigger fans on the back, but it wouldn't be Apple if it didn't suck.

Edit: To Rachel, your processor definitely should not slow down when the fan comes on. There is such a thing as variable speed processors, but those are almost exclusively used for mobile computers. I'd think it would error out if there was somehow a problem with your PSU that was draining off power from the CPU. My guess(Without knowing more) is that the fan noise is so irritating that everything just seems to be taking longer :)

Edit: If anyone else finds this a little less 'ranty' write-up is at: devrand and if there are questions or comments I will see them there, since it's rare I check this blog nowadays.