Underclocking a MAC MINI G4 to keep it cool

[Piru]

As far as I know the only way to underclock the Mini is to change the PLL multiplier jumpers.

[Piru]

@gaula92

the MAC MINI G4 can run in reduced speed: it runs in reduced seed by default and then swutches to full speed if needed.

As far as I know it doesn't. Are you perhaps confusing the fan speed changes with CPU speed changes (which AFAIK do not happen with mini)?

[Piru]

@gaula92

hmmm...those fan speed changes...aren't they related to dynamic cpu frequency scaling? I believe they are...

They aren't. The fan speed is controlled by a temperature sensor directly. It has no relation to the actual state of the CPU.

The G4 used in the mini has Nap and Doze modes which are used to reduce power usage. These however do not modify the CPU clock speed. Additionally, there is no way to remain in doze/nap mode in permanent basis (you can only nap/doze when idle).

So as far as I know the only way to make the system run cooler are:

1) clean the fan assembly, aiding the air flow (if you're unwilling to open the mini you can use canned air blowed thru the vents, even that helps a bit)

2) underclock the system via the PLL jumpers.

[Piru]

@gaula92

nap/doze modes are controller by the kernel then?

Yes, but you can only enter nap/doze when you're idle. If you have anything CPU intensive running you just cannot nap/doze.

On the other hand, how durable can a Mac Mini G4 be in full 24/7 use?

I know several mac mini servers that have run for years.

I heard they age pretty fast, so that's why I wanted it to run cooler.

I haven't heard of such problems. Obviously at times some systems die but compared to number of minis out there it's only a very tiny fraction.