G5: Temperatures & Fan Speeds Part I

Hopefully most of you with G5 PowerMacs now have Debian up and running on your system and with little to no hassle. I would now like to take a few posts to cover the temperatures and fan speeds these machines should run at on average and under heavy load while also just covering general items relating to monitoring these items.  This first post will cover just general agenda regarding the temperatures and fan speeds related to your G5.  Follow up posts to this topic will be more in-depth.

The G5's case itself is made of a anodized aluminum alloy that is combined with multiple system fans (most had up to 9!) and designated thermal zones to provide optimum cooling. Another thing to keep in mind regarding the cooling of these systems is that the different models had different means of cooling the system. Most G5 models simply used the traditional CPU heat sink method and built-in fans, such as the ones that you will see residing next to the CPU.  Certain high end models used a liquid cooling system (LCS), which tended to be prone to coolant leaks.  This led Apple to release models with a revised LCS to overcome the issues, but these can be harder to come by and seem to be few and far between. From what I have learned, only the 2.5 GHz Dual Processor (June 2004), 2.7 GHz Dual Processor, and Quad-Core G5 models had the LCS instead of the traditional CPU heat sink.

If you have a system temperature and fan speed utility installed within your OS X/Debian drive or partition, you will quickly learn that these G5 PowerMacs have quite a few hardware sensors built in you can use for monitoring which thrills me for a number of reasons. Temperature and fan RPM information can help you quickly spot current potential issues with certain devices in your system and help you pro-actively address and/or prevent possible issues down the road. Overall, they can help you increase the longevity of your G5 for years to come.  Speaking of system maintenance, I would encourage all G5 owners to check out this post from Cameron Kaiser on the topic.  Very detailed and insightful and I would say it applies in general for owners of other PPC machines as well in many regards.

Let us first review the safe operating ranges in terms of the general temperatures for our G5 PowerMacs as recommended and prescribed by Apple.  Below are links to the technical specifications for each of the 5 generations of G5 PowerMacs released by Apple along with the safe operating temperatures for both storage (not system storage, but storage in terms of its external environment) and the system as a whole.

Original 2003 Series -
  • Operating temperature: 50° to 95° F (10° to 35° C)
  • Storage temperature: -40° to 116° F (-40° to 47° C)

June 2004 Series
  • Operating temperature: 50° to 95° F (10° to 35° C)
  • Storage temperature: -40° to 116° F (-40° to 47° C)

Late 2004 Series -
  • Operating temperature: 50° to 95° F (10° to 35° C)
  • Storage temperature: -40° to 116° F (-40° to 47° C)

Early 2005 Series -  
  • Operating temperature: Not available
  • Storage temperature: Not available

Late 2005 Series -
  • Operating temperature: 50° to 95° F (10° to 35° C)
  • Storage temperature: -40° to 149° F (-40° to 65° C)

As you can see, the safe temperature ranges are quite similar across each generation. Not too much of a surprise there.  If you take a look at each of those documents linked above, you will also notice safe humidity percentage ranges and I would encourage you to review those as well because where you store and run your G5 is also an important consideration to keep in mind. I myself keep my running in the basement where it is generally much cooler but also more damp, so I keep a small dehumidifier running during times of high humidity.

So with these numbers in mind and available for reference, let us discuss the different pieces of software we have at our disposal for monitoring the system's various temperature and fan sensor values under both OS X and Linux.

  • Hardware Monitor (10.4 or Later) - Only gives temperature readings and still requires payment for full application access.
  • Temperature Monitor - By the same authors as Hardware Monitor. Basically an older version of Hardware Monitor that is a free download.
  • QuickFans - Another utility by the Cameron Kaiser for G5s, but may also work on G3 and G4 machines. However, this utility may or may work correctly though according to his notes, so use at your own risk.
  • iStat Pro - Well known and heavily used widget that is my personal favorite and go to sensor monitoring application.  Lightweight and available at the hit of a few buttons.
  • XRG - Have not personally tried this one, but it looks quite interesting as it also includes GPU monitoring as well. Only available for OS X 10.5 in terms of PPC support.
Linux (Debian)
  • Conky - A utility many of us are probably familiar with. Incredibly powerful and adaptable. Requires a bit more legwork to start reading available sensors, but it is possible as I have wrote about here.  I would recommend downloading the version available from the official Debian repositories. It does not actually have the native ability to obtain these values but gives you the tools to use other tools to output them. Makes sense right?
  • lm-sensors - I cannot vouch for this either, but supposedly others have been able to make it work with different PPC machines in the past. I am willing to give it a shot myself. Their official site would not load, so I have linked to its Wikipedia page.
  • sensors-applet - According to their page, "Gnome sensors applet is an applet for the gnome panel that displays readings from hardware sensors, including temperatures, fan speeds and voltage readings."  I see it includes support for lm-sensors so should provide similar results. No experience with this one either.

So not a whole lot to choose from, but perhaps that is a good thing? Anyways, my next couple of posts will cover some of my own actual readings using some of the utilities mentioned in this post and how they compared with each other. If you are aware of other utilities and methods at our disposal for obtaining these values, please share as well and I will add them to the lists above.

What would be really sweet was if we could build our own custom utility for Linux for gathering this PPC sensor specific system information across the different models.  Its certainly possible and I would be more than willing to help tackle it.  Let me know your thoughts!

Other than, no update yet on the Nouveau driver situation for G5s, but my hope and willingness to resolve the issues are strong.  I have actually started to write up another post on how to upgrade to Nouveau's latest drivers for testing purposes for when the time to test the fix does (and it will) come.  It is not as straightforward as one would think.