Retina Macbook Pro Different Fan Speeds?

boto

macrumors 6502
Original poster
Jun 4, 2012
437
28
I know I am paranoid, but is it normal to receive fans speeds of around 2160 RPMs on the left and 2000 RPMs to the right in normal conditions, such as web browsing, email, and other minor usages? I want to clarify if my rMBP is defective or not, since I noticed classic MBPs have similar ranges. It seems I can never get both fans to rotate at the same level, it is always a 160 difference.

.:apple:
 

Acidsplat

macrumors regular
Aug 12, 2011
206
435
I may be wrong, but one fan is on the CPU and the other is on the GPU. If you get the processor to start working along with the integrated graphics, it'll need to cool more cause they're on the same die. Since the dedicated GPU isn't being used, it doesn't need to cool more than it does idle.

The left fan covers the processor, so if the processor and/or integrated Intel graphics is working, it'll need to cool more than the GPU side on the right as its not being utilized.
 
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Puevlo

macrumors 6502a
Oct 21, 2011
633
1
It sounds like one fan is getting far less electricity than it needs to function. I'd suggest jump starting it with some jumper cables.
 
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GekkePrutser

macrumors 65816
Aug 18, 2005
1,022
338
Barcelona, Spain
I may be wrong, but one fan is on the CPU and the other is on the GPU.
Not exactly, they're both on the same heatpipe in the retina model, but one is closer to the CPU and one closer to the GPU so in that sense it is right. But they should share the load more evenly than the previous model.
 

TheMacBookPro

macrumors 68020
May 9, 2008
2,132
1
You can use smcFanControl and set it so the fan speeds are synced ;)

I'm more worried about the fact that it can't seem to read the computer's temperature though.
 

VFC

macrumors 6502a
Feb 6, 2012
514
10
SE PA.
Not exactly, they're both on the same heatpipe in the retina model, but one is closer to the CPU and one closer to the GPU so in that sense it is right. But they should share the load more evenly than the previous model.
Since the heatpipe on the right side is attached to both the CPU and discrete GPU, it may be possible that some of the heat from the CPU/HD4000 chip is being absorbed by the GPU chip and surrounding circuitry before it gets to the right fan-sink. Just a theory.....

The L/R fan speed on my cMBP is evenly matched in "normal" mode. I would expect that to be the case since the two heatpipes are exactly centered between the CPU and GPU.
 
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Tankmaze

macrumors 68000
Mar 7, 2012
1,656
274
Sorry for bringing up old post.

But just got the retina mbp, coming from cmbp late 2011. and indeed the right and left fan speed is not in sync. the left side is usually higher,
so I guess this is normal ? appreciate it if anyone can reply or confirm. thanks
 

snaky69

macrumors 603
Mar 14, 2008
5,904
484
I know I am paranoid, but is it normal to receive fans speeds of around 2160 RPMs on the left and 2000 RPMs to the right in normal conditions, such as web browsing, email, and other minor usages? I want to clarify if my rMBP is defective or not, since I noticed classic MBPs have similar ranges. It seems I can never get both fans to rotate at the same level, it is always a 160 difference.

.:apple:
Yes, you are paranoid. Yes it can happen under certain circumstances. The left fan is closer to the CPU and GPU and sometimes works harder than the right one.
 

hiranya47

macrumors newbie
May 12, 2017
1
0
India, at a computer.
I may be wrong, but one fan is on the CPU and the other is on the GPU. If you get the processor to start working along with the integrated graphics, it'll need to cool more cause they're on the same die. Since the dedicated GPU isn't being used, it doesn't need to cool more than it does idle.

The left fan covers the processor, so if the processor and/or integrated Intel graphics is working, it'll need to cool more than the GPU side on the right as its not being utilized.
You are not wrong.
[doublepost=1494631011][/doublepost]
Can anyone confirm if this is normal?
Yes this is normal.
 
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