actually, i've started wanting to get to the bottom of the problem, instead of working around it.
basically, with G5 Power Mac's, you can switch the processors between "Highest" power and "Reduced" (the difference is, for example, ~28fps video encoding to ~36 fps on highest). when on Reduced, the fans shut right up, never blowing faster, i think that was the aim of letting you choose. on highest, before the 10.4.8 update was released, the fans would potentially be like a jet taking off, so i guess they let you choose.
on highest though, the video card starts making noises, i guess that it's under stress. for example, when anything is triggered graphically (dock appearing/dissappearing, windows being moved, resized etc) it makes a sort of quiet buzzing noise, for the duration of the graphical leg-work, the goes quiet again. the other, more irritating noise is a constant 'beeping' noise, on the second, every second (or so), like a clock, except only on 4 of every 5 beats, at which point it stays silent (1, 2, 3, 4, [silence], 1, 2, 3, 4, [silence] etc). it's only quiet, but it very much audible once you know it's there. and it drives me slowly insane.
i've googled this, and apparently, using CHUD in the developers tool (what ever CHUD is), you can turn off NAP mode for the processors, and this stops the noise, but also prevents the processors from going idle. now, i pay the electricity bills here, and i don't want them any higher than they already are (the G5 not known for being economical), so i don't really want to do this. also, i can shut it up by setting the processors to 'Reduced' anyway.
my questions are these:
what is CHUD, or NAP more specifically, and i've heard that apple doesn't reccommend the procedure, so any advice would be great, and also, does any body else have this problem, and a way to solve it? the machine is out of warrantee.