MBP Late 2008 15" Overheating?

Ey guys, after getting a new 13" I have been noticing that it seldom gets warmer than 50C while in a speck case on a soft surface, while my 15" on the other hand is normally running at the high 70s and mid 80s and easily reaches the 90s if I begin watching a video on youtube when not in any sort of case and kept on a hard surface. I have been ramping up the fans using SMC Fan Control whenever I witness the machine getting warm but it makes me wonder if I have a faulty machine and is reason for me to get it checked out(it is still in warranty).

And just recently I switched to using the 9600M GT graphics card(for the first time since I got it really) and the temperatures hover at about the high 70s to mid 80s as usual but this time the fans are up to 3500-5000rpm on average without me setting anything with SMC Fan Control. Even just letting the machine idle for awhile doesn't get the fans to lower to 2000rpms(which I would assume is the expected normal speed considering my 13" seldom revs up a hair past 2000rpm).

I generally leave my 15" MBP on all the time(5 days/week), or put it to sleep whenever I am going to transport it(as I am sure most of us do). What I constantly have running is:

• Firefox(with around 40 tabs)
• Xcode or Eclipse(maybe both, but definitely one of them)
• Terminal(with a handful of tabs[3-7])
• Adium
• Preview(with up to 15 or so documents open)
• iTunes

So has/does anyone else experience what I am experiencing? Or do you think my computer is possibly going bad? Thanks.

 

One solution that goes well with SMC under load conditions:

CoolBook


I just found the optimal settings for my MBP 13 (2010). Under idle temps, it doesn't do much since it already sits at default low voltage/low clock. But when under load, I've been able to reduce the voltage from 1.0v-1.1v to 0.875v-.9.


So I'm going to go out on a limb and assume that with all those applications loading, your Macbook is constantly under load, which causes you CPU to make things hot. If my assumption is correct, undervolting using CoolBook might do a few wonders.

 

not sure I totally follow all your explanations.

When its hot, you need to check processes in activity monitor and see if something is using up the CPU a lot.

If the CPU is mostly idle and it doesn't get under 70 with 2000 rpm... then I'd pop the bottom off and make sure to clean out the fans and heatsink fins.

 

I have a 15" Macbook Pro as well and it usually gets quite warm if I were to watch any youtube video or even start a skype call or video. I have an ssd in mine as well.

 

I would install iStat Pro and see if an app is using most all of the cpu. I had an addon for firefox go wild and was causing my MBP to over heat. iStatpro showed which app then I went looking. The culprid was adblocker, apparently an updated did not work. Uninstall and reinstalled fixed my problem.

istat did nothing to fix the underlying problem, so check a little deeper.

 

Interesting thought, but I am not too keen on going that route. The CPU is already underclocked as it is and I would rather have the system working properly without resorting to those sorts of measures. Thanks for the reply.

Define "mostly idle". Looking at activity monitor the CPU's %idle is hovering between 77-85% and the system is round ~80C with fans at 2500rpm(set by me via SMC Fan Control). I may take your suggestion and clean out the fans. That will have to wait till summer when I have more time on my hands though.

I don't have an SSD in mine, I have the stock HD that came with it which is the 320GB 5400rpm HD.

Funny thing is I do normally use iStat Pro for monitoring my system, but just recently it keeps on disappearing from the dashboard. I reinstall it and the option of replacing it comes up and I do so and I am able to view the iStat Pro widget for a bit, but sooner or later it disappears again... This has only been happening recently and only with that widget, so naturally I don't have the energy to reinstall it every time I want to view system stats. I just use the tiny indicator that SMC fan control gives me about CPU temperature and fan speed. I am using 10.5.8 by the way.

So currently I am resorting to using Activity Monitor and it shows that Firefox is hogging most of the CPU, but I don't have any add-ons for firefox at all, so an add-on being the culprit is not possible. I do have an incredibly insane number of pages open though.

Oh and at the time I finished writing this response the temperature is hovering around 80C still but now the fans are up to 3300 rpms set by the system automatically(when previously noted I had set them via SMC). Thanks for the responses.

 

mostly idle would be like... 0% to 5% CPU usage... if your is stuck using over 70% you need to look at what app is using it so much... you should be able to see that in activity monitor.... and figure out why its doing that. constantly using the processor that much will create a lot of heat, so your heat sounds pretty normal for that much CPU usage.

 

No, you are looking at it wrong. I am looking at % idle not usage. I did it this way because otherwise I would have to look at % User and % System separately to determine total CPU utilization, and it is easier to gauge the usage by looking at just one category. So I am only using about 15-23% which really isn't very much.

 

ok I misread that.. didn't notice you said %idle

mine is about 95% idle with Safari and Activity monitor running.

My 15" late 2008 (which I need to sell sometime soon) isn't much different... it will sit around 75º even if its only using 20% of the CPU. If I max it out, the fans have to spin 6200rpm just to keep the thing down to 85º. I do this a lot... I already had to replace a fan in it a few weeks ago that was already starting to make noise from overuse. These are nice laptops, but they just run hot. seeing it 80 and 90 is pretty common while doing things. My new 13" is MUCH MUCH cooler. but overall, I don't think your seeing anything uncommon. A bunch of people (including me) were complaining massively about the temps of these things when they first came out.

I tried out the Coolbook thing and it didn't work... it reported back to me that it was 10º cooler, but all the other temp programs were reporting 10º hotter than Coolbook, like Coolbook was just lying to me.

 

I see, thanks for the feedback. How fast do your fans usually spin at? Mine are currently spinning around 3500-4000rpm to keep it at 74C. I am of course using the 9600M video card instead of the 9400M. Also how hard was it to replace the fan(if you did it yourself)? How much did it cost? Thanks.

 

I don't have OSX on it currently to test.. I didn't need it for OSX right now and needed a few weeks to work on a project with a windows machine, so I have a Windows hard drive in there right now.. not dual booted.

From what i remember though... I barely ever use(d) the 9600. It does get much hotter with the 9600 enabled, even if your not doing anything. But it would sit at 2000 rpm and around 75º with the 9600 enabled... but spinning up to 3k or 4k didnt down the temp much.... with the 9400M going it would be 2000 rpm like in the 50s mostly idle. Yours sounds a tad on the hotter side... it might just need to be cleaned out.

The fan was ridiculously expensive (like $45-$60 depending where you get it) and the right and left fans are different molding so you have to get the right one... Its the first Mac I've ever gotten without Applecare, and only the second thats ever had anything go wrong with it... so had little choice. I've opened up and replaced every part on so many thousands of laptops, I could swap it in my sleep... but even if you've never opened any laptop before, I'd say its pretty easy. Just take off the whole bottom cover... then 3 screws holding the fan in, and the plug just snaps down onto the motherboard socket for it... it takes 3X longer to get the cover off than it does to swap the fan.