Fan speed up on DP 1.25


macrumors 6502a
Original poster
Dec 1, 2002
I just wanted to ask about an interesting item that happens to my 1.25Mhz DP.

When i shut it down sometimes the fan speeds up to an almost unbearable sound level, maybe this has something to do with the machine overheating at certain points but it gets damn annoying..

anybody else have this?


Jun 22, 2001
On my Dual Ghz that happens it will go to literally vacuum level for 1 second upon startup. It is normal I have heard many other people talking about it. Don't worry.


macrumors 65816
Oct 9, 2002
Sydney, Australia
i had this happen to on my DP 867 at startup.

what it is, is that the fan manangement part of OS 9/X hasnt cut in yet. Therefore the fan is running at full speed according to the BIOS (yes macs have em). When OS 9/X starts up then it gets the data from the fan control chip and adjusts the fan speed according to what the temperature sensors in the motherboard tell it.

The latest PM G$ firmware update fixes this almost entirely.

I cant tell you now how effective it is as i hav o/clocked my G4 to a DP 1ghz.

Hope it helps
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.