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Fixing an overheating Mac Pro - no expense required

mac-overheating.jpgLately my Mac Pro has been crashing and freezing with greater regularity. From prior experience with computers crashing, and it being the summer (and a particularly hot one in London!), I had a hunch it was heat related.

Weird artifacts on the monitor display (strange green and pink blocks and lines) clued me in that it might be the Radeon X1900 display card that was the cause of the overheating, and a bit of searching around on the Internet showed that this card has something of a reputation for overheating. The solutions people talk about all seem to revolve around removing fluff from the fan ingest (did that), purchasing after market coolers (not cheap and quite complicated) or buying a new card (even more expensive). I wanted to find something else.

The first step was to confirm that it was heat related. I shut down the computer, opened the case, and let the computer cool down for an hour. When I started it up again the computer lasted longer before crashing than normal. A good clue.

I went looking for a way to see what the temperature actually was inside my Mac Pro. There are several methods for doing this but I found a wonderful free utility called Temperature Monitor. This shows you the temperature for many points within the machine and can graph them over time. A very useful tool indeed.

Although Temperature Monitor did not show a specific temperature reading for the graphics card itself, two readings in particular seemed high and are indeed physically close to the graphics card - the Northbridge and Memory Module B2. Both were up around 80 degrees C which is definitely a little hot.

I used another free utility, the brilliant SMCFanControl to adjust the speed of the fans within the computer. While running the history graph feature of Temperature Monitor I first turned all the fans up to full and immediately saw nearly all temperature readings within the Mac Pro go down. It was amazing to watch. After some fiddling I set the PCIe/HDD fan to a minimum speed of 1700 rpm which brought the Northbridge and Memory Module B2 temps consistently down under 70 degrees. I left the other fans in the end at their default settings.

Since then I haven't had a single crash and I've not spent a penny. I've created different profiles within SMCFanControl (Normal, 1/2 cool down, 3/4 cool down, full cool down) and can instantly change the speed of the fans at will, depending on the ambient temperature.

Now if only I could get a speed increase utility for my air conditioner...

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Excellent post, as usual you reveal great information to make life much better at no cost. Can I get a version of SMCFanControl for my brain?

This definitely works -- I have a Mac Pro dual quad that has been crash prone since 10.5.2 getting progressively worse thru 10.5.7 -- worked fine with 10.5.1 -- would only run for 1-2 hrs at a time -- I went through a zillion other options before seeing this article - I sped up the fans and haven't had a problem since. I wonder if it's not the graphics card - I was starting to get odd mouse and keyboard problems too -- the ATI Radeon 2600 firmware update with 10.5.2 may be a cause, can't see the card fan operating -- also I'm guessing the newer op systems may be placing a larger load on the system -- ??
Good tools regardless - thanks for the info

Thanks for the hint; definitely helped me bringing temps down in my MacPro early 2008, 16GB mem and 4x450GB SAS @15000rpm

Thanks for the great post from last year. I am wondering though if making the fans work hard like this will cause them to wear out quicker. The daily - and several times a day if the computer is on for extended periods - heating up and cooling down - can this be good for the Mac? This is good as a temporary solution, but I am wondering why my Mac - Tiger 10.4.11 - has suddenly started heating up like this (in the evenings too, when external temperatures are not high), and how to tackle this root cause whatever it may be. Unlike your problem, in my Mac all the positions can rise in temperature to between 60 and 68 degrees, other than the SMART disc, which stays in the mid. 30's. I'm using the temp monitor application to know this and the fan control, but do you have any other ideas?

Simon, thanks for your comment. You are correct that it is generally going to lead to quicker wear of the fans by running them at a higher speed. The worst that can happen however is that the fan dies (or gets so noisy) that it needs to be replaced. For me this was a better option than replacing the more expensive video card, for a problem that only manifested itself in my case in the high heat of summer. I have in the two years since writing this article subsequently replaced the video card which was the root cause of my problem. In your case it's hard to say what is the cause, but fluff buildup, a failed fan or badly mounted heatsink are the most likely culprits. Good luck.

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