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Penryn MBP Idle Temperatures

Dragonforce

Dragonforce

macrumors 6502a
Original poster
Apr 9, 2008
587
5
Germany
Hi everyone,

yesterday night I got bored at our company, and while I was alone I turned on all 4 MBPs and left them running for 30 mins with 98 - 100% idle. I noticed that theres really big differences in the idle temperatures between those MBPs (all of them are the early 2008 2.4 GHz Penryn stock models, except they all got 4 GB RAM)

MBP #1 showed 38°C / 100°F CPU and 46°C / 115°F GPU
MBP #2 showed 45°C / 113°F CPU and 55°C / 131°F GPU
MBP #3 showed 46°C / 115°F CPU and 57°C / 135°F GPU
MBP #4 showed 42°C / 108°F CPU and 50°C / 122°F GPU

Each machine got its own desk made out of the same material with plenty of space, ambient temperature was exactly 21°C / 70°F. All of them were idle, fully charged, with the MagSafe plugged in.

So, I have a few questions:

Q #1: Why is the GPU always more hot than the CPU (it got nothing to do ?)
Q #2: Why does MBP #1 almost run 10°C cooler than MBP #3 ?
Q #3: Why does the GPU heat up together with the CPU ?
e.g. I use CPU test (Glucas Test) which is supposed to cause only load on the CPU... so the CPU went to 80°C, but the GPU does go up to 85°C as well ?

Also, I'd like to hear your Penryn MBPs idle temperatures, especially of your GPU.

Thanks for reading,
Kind regards,
Alexander
 
Dragonforce said:
Hi everyone,

yesterday night I got bored at our company, and while I was alone I turned on all 4 MBPs and left them running for 30 mins with 98 - 100% idle. I noticed that theres really big differences in the idle temperatures between those MBPs (all of them are the early 2008 2.4 GHz Penryn stock models, except they all got 4 GB RAM)

MBP #1 showed 38°C / 100°F CPU and 46°C / 115°F GPU
MBP #2 showed 45°C / 113°F CPU and 55°C / 131°F GPU
MBP #3 showed 46°C / 115°F CPU and 57°C / 135°F GPU
MBP #4 showed 42°C / 108°F CPU and 50°C / 122°F GPU

Each machine got its own desk made out of the same material with plenty of space, ambient temperature was exactly 21°C / 70°F. All of them were idle, fully charged, with the MagSafe plugged in.

So, I have a few questions:

Q #1: Why is the GPU always more hot than the CPU (it got nothing to do ?)
Q #2: Why does MBP #1 almost run 10°C cooler than MBP #3 ?
Q #3: Why does the GPU heat up together with the CPU ?
e.g. I use CPU test (Glucas Test) which is supposed to cause only load on the CPU... so the CPU went to 80°C, but the GPU does go up to 85°C as well ?

Also, I'd like to hear your Penryn MBPs idle temperatures, especially of your GPU.

Thanks for reading,
Kind regards,
Alexander
Click to expand...
#1: The 3D effects and eye candy is powered by the CPU.
#2: Variations in heat conduction; varied thermal paste usage; environment
#3: It's all one connect by one heatpipe. Heat transfers from hot to cool so if the heatpipe is hotter than the GPU, the heat will transfer from the heatpipes to the GPU.

Mine:
f70ada22.png
 
Hey alphaod,

thank you for your reply, especially the answer to my 3rd question sounds pretty interesting / logic. Also thanks for the iStat screenshot - those temps are almost the same on my MBP (+ - 2°C)

I would appreciate it, if anyone else would share some screenshots of their own Penryn MBP when it has been sitting idle for a couple of minutes.

Thanks again,
Alexander
 
Mine is the same as alphaod's (+-1).


Were all the machines you tested fully charged?
 
Yes, it was like 2 AM in the morning and everyone was at home except me, so I took my chance to test this out before I went home as well. All the machines have been switched off for a couple hours (cold boot), all of them were fully charged and were in the same room with basically the same software installed.
 
here are my temps just browsing this page in safari (Penryn MBP)
 

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. . . 12.5 hrs walltime; fancontrol installed & active - min set at 1500rpm.
 

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I finished watching a 2 hour movie in iTunes 5 minutes before I took this pic. The temps are what I usually average on a day to day basis...


Picture 1.png
 
MacBookProJoe said:
How are you guys taking those snap shots of your screen please....
Click to expand...

Command-Shift-4 is select screenshot. If you press the Space bar after hitting the previous sequence of keys, it will turn into a take selected window.

Chali427 said:
these are the temperatures when my 2.6ghz mbp is at about 90% idle, is it normal???, I think it is too hot...:eek:
Click to expand...

90% idle? Do you mean 10% used? Also on both cores? The temperature seems about right-- 135F~57C. I usually manually set my fan to 6000RPM to cool the computer down if I need to.

Burgess07 said:
I finished watching a 2 hour movie in iTunes 5 minutes before I took this pic. The temps are what I usually average on a day to day basis...


View attachment 115512
Click to expand...

Is the room cold?
 
Wow those temps are cool.. my rev. B MacBook runs at 60-64C doing basic stuff when plugged in and 55 when unplugged O_O

Edit: all with ambient room temp at 23C (rather cold lately :( )
 
Great Success!

2.33C2D with many Dashboard items open and Safari open for the last few hours :)
 

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