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max fan speed on retina 15
- Thread starter vbman213
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I would also say it's normal.
Here's a sample from my mid-2012 15" 2.7/16/768 (all CPUs at 100%):
My 2¢ worth: just let the system handle the fan speeds and enjoy. The controller has algorithms which will keep temps and noise levels at optimum levels. When the system is doing light work, running the fans faster (I assume that's what you want the manual speed control for) isn't going to make much difference to an already cool machine and will needlessly use more power (I can only speak about my particular machine - it's always barely warm along the top of the keys and bottom.) When it is under load, the fans will increase speed above your set minimum anyway.
Here's a sample from my mid-2012 15" 2.7/16/768 (all CPUs at 100%):
5935 RPM Left
5503 RPM Right
5503 RPM Right
My 2¢ worth: just let the system handle the fan speeds and enjoy. The controller has algorithms which will keep temps and noise levels at optimum levels. When the system is doing light work, running the fans faster (I assume that's what you want the manual speed control for) isn't going to make much difference to an already cool machine and will needlessly use more power (I can only speak about my particular machine - it's always barely warm along the top of the keys and bottom.) When it is under load, the fans will increase speed above your set minimum anyway.
I do not know if it is related, but I remember reading something about a new asymmetrical cooling assembly/ fan design to keep noise down; perhaps the two fans are at different speeds to reduce sympathetic frequencies that would occur with BOTH running the same speed and through the same cooling tunnels.. Not sure if that is the case here, but would make sense to me, in an Audio Engineering kind of way.. 
I do not know if it is related, but I remember reading something about a new asymmetrical cooling assembly/ fan design to keep noise down; perhaps the two fans are at different speeds to reduce sympathetic frequencies that would occur with BOTH running the same speed and through the same cooling tunnels.. Not sure if that is the case here, but would make sense to me, in an Audio Engineering kind of way..
I briefly thought about that, but the difference of a couple hundred Hz could still be noticed as a beat, if the intensity were enough. I think it's more to do with the thermal distribution in the heat pipe. IIRC, the discrete GPU is on the same side as the faster fan.
The asymmetrical design is done by placing the blades at varying spacing about the hub (some groups closer, some farther apart). When rotated, they cause air movement at different rates, the idea being to spread the energy across a wider range of frequencies. Someone (around the time of the rMBP launch) recorded the audio of both a rMBP and one with symmetrical blades. It's pretty easy to hear the difference, and if you have an audio app that can display a spectrum or waterfall display, you can easily see the difference in energy distribution.
My previous machine, an Early 2009 17" UB, did have fans at the approx. the same speed, with just a few Hz difference. If there were an audible beat, I'm sure I would notice it (my ears are too sensitive at times ). I believe my earlier MBP and PB also ran at the same speed.