Comment 52 for bug 34723

With a Powermac G5 (Powermac9.1) if you run Leopard the temperature in the lower HDD is bellow 45 degrees Celsius. With Ubuntu 10.4 (and summer) you get the same HDD at 57 degrees Celsius or more. Opening the side tower made the fans run at full speed, and the HDD becomes cool again.
The only message at boot (beside performance governor already fixed as in guides in the Powerpc FAQ) is related with windfarm not loaded (all those messages say about windfarm not loaded) but look like the problem is not with modules.
Here is why, Leopard was patched due to the bad location of the HDD sensor in Powermac G5 first models. the Fan Speed table look like is not the same as in Leopard because the HDD fan with Ubuntu does not run at more speed to get the HD cool.
I do not know how to change this tables,
But the system still runs more hot with Ubuntu 10.4 than in Leopard (about 10 degrees Celsius)
This issue has a side effect: the HDD stop responding after several hours running hot, this is reported by SMART as a Warning (show in the Hard Disk tools from Ubuntu) this warning say that the Disk is more than 50 Celsius in average, yesterday was 61 average and stoped responding for several hours after i found that opening the side made the fans run at full speed and keep it alive but i switch back to Leopard to see what is the diference and as i write before i found a difference in temperatures in both OS. Of course i remeber the HDD bad sensor documented in www.xlr8yourmac.com and some workarounds before Apple patched Leopard.

Thank you