Asymmetrical fan speeds on 15" rMBP with dGPU?

[FuNGi]

Hi,

I know this is a silly observation but I wanted to get some feedback from the MR community. I've noticed that my new 15" rMBP with the 750M dGPU has asymmetrical fan speeds. The right fan consistently runs at higher rpm's. I at first assumed that it was due to the asymmetrical location of the dGPU but based on the teardown pics it actually looks like the dGPU is on the left side of the logic board.

Do other's notice asymmetrical fan speeds on their higher end rMBP's? Is it also seen on the lower-end 15" rMBP's with only the Iris Pro iGPU?

pics are from iStat Pro and ifixit.com (2012 version with dGPU in red box):

 

[Nismo73]

Hi,

I know this is a silly observation but I wanted to get some feedback from the MR community. I've noticed that my new 15" rMBP with the 750M dGPU has asymmetrical fan speeds. The right fan consistently runs at higher rpm's. I at first assumed that it was due to the asymmetrical location of the dGPU but based on the teardown pics it actually looks like the dGPU is on the left side of the logic board.

Do other's notice asymmetrical fan speeds on their higher end rMBP's? Is it also seen on the lower-end 15" rMBP's with only the Iris Pro iGPU?

pics are from iStat Pro and ifixit.com (2012 version with dGPU in red box):

I believe in the pic that the logic board there is turned 180 degrees, so the dGPU is actually on the right side.

 

[FuNGi]

I believe in the pic that the logic board there is turned 180 degrees, so the dGPU is actually on the right side.

Ah, you're right. It is a view from the bottom of the laptop. I suppose the right fan is tuned to preemptively cool that chip a bit more regardless of if it's even in use then. Wondering if this is real or if the fans just vary from unit to unit.

 

[sholzer]

2.3/16/512 here and my right fan is also spinning about 200 RPM faster at idle (2160 vs 1990)

 

[laurihoefs]

Ah, you're right. It is a view from the bottom of the laptop. I suppose the right fan is tuned to preemptively cool that chip a bit more regardless of if it's even in use then. Wondering if this is real or if the fans just vary from unit to unit.

If you search for threads concerning rMBP temperatures, you'll see many screenshots showing a similar difference.

I can also confirm it on a 15" mid 2012 rMBP.

 

[SimonTheSoundMa]

Do not use iStat Pro, it measures wrong for the rMBP and doesn't include all of the sensors.

The left side fan goes from 2200 - 6200 RPM, right side 2000 - 5600 RPM. Nothing to worry about.

The GPU will overclock when it is below 80°C and start to underclock when above 100°C. The 750M will try to run around 80°C as much as possible. The CPU runs anywhere between 600MHz and it's maximum Turbo Boost speed, get to around 95°C when all 4 cores/8 hyper threads are running and clocks down to their normal speed 2.0/2.3/2.6GHz.