Hot 'Book? It Could Be Your Apps

Since I installed 4 GB of RAM in my Late 2008 Unibody MacBook, I've found I can go for very long periods of time without rebooting to clear the memory heap, without noticing a substantial slowdown in performance.

For example, the other day I realized that I couldn't remember the last time I restarted my computer. I'm virtually certain it had been over a month earlier, possibly even six weeks or two months.

Running Hot

However, I watch Temperature Monitor like a hawk, and I had begun noticing that the MacBook was tending to run a lot hotter than usual, the processor temperature often climbing into the low 80s Celsius, while I had previously found the typical range to be in the high 60s, depending somewhat on ambient environmental temperature. While we've been having warmer than normal (by a lot) temperatures here in Nova Scotia for most of the winter and spring, the 'Book was still running hotter than I recalled from last summer.

I usually have a lot of applications running - four browsers, usually two or three image editing applications, a couple of text editors, email software, and several utilities. My suspicion had been that browsers are one of the worst heat generating offenders.

I really detest fan noise - even with the relatively unobtrusive little fan in the Unibody MacBook - and I also prefer to keep my computers running as cool as is consistent with doing the job I need to do with them.

System Maintenance

I decided that since I'd downloaded (but not yet installed) the Apple Security Update 2010-002 for Mac OS X 10.5.8, a kill-two-birds-with-one-stone reboot would be in order - and hopefully help cool things down. Actually three birds. I like to run a set of system maintenance routines - Repair Permissions; run the daily, weekly, and monthly cron scripts (I don't keep my computer up and running all night for them to run automatically at the traditional times, although I think I heard somewhere that the system will get around to it sometime regardless); and various cache dumps at least once a month or at reboot time, if the interval is longer than that, so I was overdue.

My favorite tool for this job is freeware OnyX's convenient "Automation" routine, which lets you custom tailor your maintenance runs using checkboxes and then just let it do its stuff, but there are a dozen or more other system maintenance utilities that will get you there as well.

Apps and Temperature

OnyX requires that all other applications be shut down while it performs maintenance, and I noted that without the browsers and Thunderbird (I'd been using version 3.1b Lanekai lately) up and running, the processor temperature almost immediately dropped by 10° to 14° C. This intrigued me enough to try closing and starting up the browsers and Thunderbird separately. The main browser culprits turned out to be Chrome and FireFox, which spiked the processor temperature from 57-58° C to 64-66° C and 68° respectively when idling. With just Opera 10.5.0 running and the others, along with Thunderbird, shut down, things cooled again to a very tolerable (and fan noise-free) 57-61°. Starting up Chrome (version 5.0.371.0) pushed the temp up to 64-66°, and adding Firefox (version 3.6.3) boosted the temp to 66-68°.

Starting up Thunderbird 3.1b1, with Opera the only browser running, drove the temp up to 66°, but I discovered that running the T-Bird 3.0.3 final version dropped it back to a more respectable 59°, so it appears that the Mozilla.org folks have some cleaning-up and optimizing to do with the T-Bird version 3.1 code. Running T-Bird 3.0.3 and Firefox 3.6.3 simultaneously didn't raise the temp further, remaining in the 67-68° range when idling or under light load, such as typing.

Cooler After Restart

The maintenance run took maybe 20 minutes, and the Security Update install considerably less than that. All went smoothly, and upon rebooting twice (for OnyX and then the system update), I noted that even with the browsers relaunched, I was now getting processor temperatures in the 62° to 74° range upon restart - better than the low 80s it had been running often during the past several weeks. Shifting to text entry (browsers still open but idling), the temp dropped into and stayed in the mid-high 50s and low 60s, and for the most part, processor temp stayed in the 60s, substantially lower than it had been prior to the maintenance routines and Security Update install - the effect of the latter, if any, on temperature being an imponderable.

Quietness and serenity were restored, and my MacBook is running cooler than it had been, which is great.

I will be interested to see how this issue is affected by installing Snow Leopard, which I finally bought a copy of but haven't gotten around to installing yet. If it helps cool things down a few notches, I'll consider the upgrade well worth it, but I'm still waiting impatiently for a Snow Leopard compatible version of WindowShade X, of which there is as yet no sign, and there haven't been any progress updates on the Unsanity Software news blog for some time either, which has me increasingly concerned.

Anyway, if your laptop is getting a bit sultry and you haven't rebooted or done any system maintenance for a while, it's well worth giving it a shot, as well as keeping an eye on which browser and email software you're running.