2010 Mac Pro, Overheat, Fans Won't Speed Up

I know this is an old thread but I am going to give my numbers anyway since I have something wrong.

I am measuring temps and fan speeds using iStat6 on a Mac Pro 4,1 (2009) with dual CPUs.

Booster 1 fan: 0 RPM; Booster 2 fan: 5200 RPM

CPU A temp (Tdiode): 54C; CPU B temp (Tdiode): 42C. The heat sink temps are about 4C cooler.

All other fan speeds seem normal. That 5200 RPM is just crazy and noisy so I am trying to figure out how to fix it.

The Booster fans cool the processor tray. You can download the Mac Pro 4,1 (2009) shop manual here. Check out the processor cage fans on page 151 to see how to get to them and how to replace them. You may need to simply clean up #1 to get it working since #2 is running that fast because it's doing the work of both.

d10nisius wrote:

Does anyone who owns a 2009 or newer mac pro ever hear their fans speed up?

I can't say that I've noticed but I use smcFanControl and boost the fan speeds manually when the operating temperatures go up. Apple tends to value quiet over cooling; the fans do tend to speed up a bit if the Mac is working hard but not as much as I would like so I don't wait.

What you might check is, first, that all the fans are actually working, and second for any dust buildup which might inhibit cooling.

I've found Temperature Gauge on the App Store to be helpful for measuring both temperature and fans speeds especially because the fan speed graphs will show the minimum speed and how much the actual speed might be above it. That will give a hint that the internal temperature controls are actually working. For example, right now, the default BOOSTA fan speed is 800 RPM but the fan is actually running at 1070 RPM. Given how it's buried in the CPU heat sink, I doubt I could tell the difference by ear.

d10nisius wrote:

...I tried the the temperature gauge, but for whatever reason it didn't work correctly on my mac pro(2010)...

Initial, that app, which was originally called '"Check My Temp" didn't work properly with my Mac Pro either, but updates got it working better.

...Does your fan ramping up pretty often? When it is speeds up, can you tell me what your cpu core temperature?...

Using smcFanControl, both one of the fan speeds and one of the temperature readings is always in the menu bar. When I see it approach 100ºF, I switch to a higher fan speed combination, so I'm usually ahead of whatever SMC will eventually do automatically. Right now checking Check My Temp, and using Apple's default fan speed settings, CPU A Core is 152ºF, its heatsink is 90ºF, the BOOSTA default fan speed is 800 RPM but the actual speed is 1070 RPM. Of interest is that the iStat Pro reading for CPU A is also 90ºF, suggesting that it may not be reading the core temp, assuming that core temp reading is correct. Ambient is about 68º. One thing that may make a bit of difference is that I'm filtering the air in the CPU tunnel (the bottom section with the intake fan up front, the CPU fan in the processor tray, and the exhaust fan in back) since that's the hardest to clean out. That may restrict the air flow a bit but the filter does capture dust and, especially in warm weather, I make sure to keep it clean.

AHT only works with the OEM DVD present.

I thought even, 0, 2, etc were actual and odds were virtual / logical cores but whatever.

85*C is not nice and fans are not - so have you tried SmcFanControl current version and manually set a profile for various fan speeds? new default 900, medium 1100, etc?

Is this "stock" or did you upgrade the processor? very common to do and put W3680 in yourself.

Even if not you may want to check the how to on MacRumors and redo thermal "paste" and clean the head.

Even Intel is not totally public but that is who would know and to ask and research but TjMax gets more complex in ways

Seeing as it is partially software, have you tried a trial test clean install with just Mac Apple OS?

I trust the developer of HM over any of the others and he has 'chimed in' at one time about sensors and Intel and knows his stuff, and was/is accurate where sometimes others were off.

d10nisius wrote:

Thanks again for the reply.

I'm testing the smcFanControl. It seems to be working fine. I'm able to create different profiles and bump up the fan speed manually. It just seems pretty silly for me to have to babysit what supposedly a professional workstation.

If you spend a lot of time looking through the posts on the various Apple forums, you'd be amazed at how much complaining is done about too much fan noise and how uncommon concern about overheating is. As computers move more and more in the direction of phones and fashion accessories to meet the changing user profile, I expect that cooling will move even further down the priority list just as simplification of use becomes more important for "low-information" users; manufacturers recognize this and adjust their designs accordingly. So the professional user has to act defensively, but fortunately I think is up to the task.

Try a can of dust off. 🙂