Cool trick. However, it also defaults back to 2 cpus instead of one even if you had preselected one. Two CPUs in nap mode will eventually crash the machine. However, if I switch to single cpu when turning on the nap mode, it will not crash. How to switch to single CPU inside of the same script?

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So this is for a single CPU MDD machine then?


Adding this line to the script ought to do it:

click radio button "Single CPU" of radio group 1 of window "Hardware"


Which makes the script go like so:

tell application "System Preferences"
activate
set current pane to pane "Hardware"
tell application "System Events"
if not UI elements enabled then
display dialog "GUI Scripting is not enabled. Enable?"
set UI elements enabled to true
end if
tell application process "System Preferences"
set napModeBox to checkbox 1 of group 1 of window "Hardware"
if value of napModeBox is 0 then
click napModeBox
end if
click radio button "Single CPU" of radio group 1 of window "Hardware"
end tell
end tell
close the first window
end tell


That should do. I've got no single CPU MDD to test this on. Seems like the preference panel isn't rightly indicating how many CPUs are in use. When I select single CPU mode, the next time I bring up the panel it shows dual mode again. You say you can tell by whether the machine eventually crashes. If so, post. Good luck.

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Are you saying that with Nap mode & selecting two processors, that it crashes Dual processor MDD Powermacs on 10.5? after how long?... because with Nap, mine doesnt crash on 10.4 with two 1 ghz processors! I wouldn't want to upgrade to 10.5 if that was the case.

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Works perfectly well. I have a dual processor MDD, running Leopard, nap mode enabled, uptime three days including some real work.

The system temperature right now is 109.4F, instead of the 137F it would generally be without nap mode. No performance penalty, much quieter operation, less heat stress on the components, and wonder of wonders, I get to use the new Xcode. No regrets.

Here's what I make of the previous comment: I think the previous poster had a single processor machine, that the Hardware panel running under Leopard can't determine whether the machine is in dual or single processor mode so it leaves the dual processor mode radio button set by default when it opens, then when it closes it finds that radio button set, and so it sets dual processor mode, then that lead to weirdness on that person's single processor machine.

Long story short, the working theory is that if someone with a single processor machine uses the script given above which explicitly sets single processor mode, it ought to be fine.

Anyone with a single processor machine having weirdness ensure?

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What CPU (745x) and CPU version do you have? I got a machine running dual 7450 rev 2.1 without any trouble in NAP mode.

Not all 7450 models seem to support napping in dual CPU configuration though. Perhaps the reason Apple removed the feature in newer versions.

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