Two Retinas running same software, one is 30 degrees F hotter?

Question

Two Retinas running same software, one is 30 degrees F hotter?

I recently bought two Macbook Pro Retina's for work (both are the same spec, 2.6/16GB/256GB). I've installed the exact same software on both and when I run them next to each other, I can see one is running about 30 deg F hotter than the other one. The main temperature difference is in the CPU Die - Digital and GPU Die - Analog.

The hotter one also has problems running my home monitor configuration which comprises of 2 1600x1200 Dell 2007FP with a 2560x1600 Dell U3011. In this configuration, the computer never goes below 180 deg F, which means that as soon as I start doing stuff, the fans start revving and eventually it starts throttling. I took the hotter one to Apple (I got AppleCare on both) and they ran the Cooling test and it came back OK.

Are these just standard manufacturing differences? I'm considering re-applying the thermal paste in the hotter one (that's the only thing I can think of that's making such a difference) but I don't know if that really helps the resting temperature or the temperatures under load. Also, even though I'm comfortable with the procedure, I'd prefer to not take the risk if it was unlikely to help.

Any ideas? Are there configuration things that I might have overlooked that would cause such a temperature difference? I'm using iStat Menus to monitor the temperature.

MacBook Pro with Retina display, OS X Mountain Lion (10.8.2)

Posted on Jan 23, 2013 12:14 PM

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Answer 1

Courcoul

Level 6

18,726 points

Jan 23, 2013 12:22 PM in response to heythisisdave

Open Activity Monitor and sort the processes out by CPU usage, just to be sure that both are running exactly the same stuff. If it turns out that both are indeed identical in config (HW & SW), AND "recent" is 14 days or less, take the hot one back for refund and get a good one instead.

NO, "reapplying" thermal grease on a Retina sounds like a surefire way of destroying it. Many critical components are glued on for support and lifting the logic board off to get to the heatsinks where the goo goes is pretty hairy if not impossible. Visit www.ifixit.com in their repair section, where they have several Retina teardowns so you can see what I mean.

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Answer 2

Jan 24, 2013 8:54 PM in response to Courcoul

I'm past the 14 day return period. Do you think AppleCare will be able to give me any insight into this problem or am I out of luck?

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Answer 3

Jan 24, 2013 8:57 PM in response to heythisisdave

heythisisdave wrote:

Do you think AppleCare will be able to give me any insight into this problem or am I out of luck?

you'll never know if you don't call.

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Answer 4

Courcoul

Level 6

18,726 points

Jan 24, 2013 11:23 PM in response to heythisisdave

Besides whatever insights the Apple techs may offer, one surefire way of ruling out the software as a cause would be by cloning the good unit into the bad one. Quickest way is via a Thunderbolt cable, though that will set you back by about $40.

First start up the bad Retina in Target Disk Mode: http://support.apple.com/kb/HT1661 (we're substituting the Firewire cable with the Thunderbolt). Ensure that the bad Mac's drive shows up in the good Mac's desktop.

Now reboot the good Mac into Recovey Mode by holding down Command R prior to the chime. Go past the languages screen and choose disk repair (bottom option). Make sure both drives, the good Mac's internal and the bad Mac's thru the Thunderbolt link, are visible.

The fun starts here. Select the Macintosh HD volume on the bad Mac's drive and Erase it to ensure no crud remains. Click on the Restore tab, choose the good Mac's Macintosh HD volume as the source and the just erased bad Mac's volume as the destination. Click Restore. Let it finish. When done, the bad Mac's drive will contain an exact copy of the contents of the good Mac's drive.

Quit and shut the good Mac off. Shut the bad Mac off (press power button). Disconnect. Start 'em up and test.

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