powermac differences

[Kronos]

I'm quite sure everything above the 2x2.3GHz is watercooled.

2.7GHz are defintly watercooled (unless there are 2 versions which doesn't seem to be the case).

G4 QuickSilvers only feature simple fans with buildin (primitive) temp-sensor. Replacing them with quality fans and adding some "smart" fan controller makes a huge difference.

Note

G4 No1 1.8GHz 45°C 3800RPM
G4 No2 (unused) 1.8GHz 44°C  3200RPM
Case 41°C 1300RPM

Yes it's audiable, but surely far less noisy than a MacMini under load (which makes no difference on the PMac).

[Kronos]

@Iggy
1x PSU 1xcase and there should be a smaller one at the back (just were the CPU-module sits) but this may depend on CPU-speed.

Mine had those 3 + 1 on each CPU (so 5 total).

I replaced the PSU with a passive one (conversion from a standard ATX-PSU) but I would advise against it as it seems the PSU-fan is very important for the air-flow in the QS.

I bought an cheap 3 channel fan-controller for 3.5" bay and mounted it beneath the CD-ROM (removing the 2nd drive cover may look ugly but allows to monito temps and RPMs).

I than bought a bunch of 3-pin fans in the same sizes as the orginal ones (when it came to how many db/A and much much air/s I just had to take guesses).

Channel 1 : main CPU (read the one used by MorphOS)
Channel 2 : 2nd CPU + small rear fan
Channel 3 : case

Sensor 1 : in cooler right above main CPU
Sensor 2 : in cooler as far away as possible from main CPU
Sensor 3 : above CD-ROM

I might add a PSU fan or move the whole thing to a (bigger) PC-case in order to maximize airflow as the case gets a bit hot for my taste.