DGPU and Loud Fans?

Discussion in 'MacBook Pro' started by kenmitchell1969, Jun 2, 2011.

  1. kenmitchell1969 macrumors newbie


    Jan 29, 2009

    I have a 2011 15” MBP, 2.2 GHz 8GB RAM with a 240GB Vertex 3 6G SSD in as the boot drive.

    The system works very well and is fast as #@!

    ...But there is one problem that is driving me nuts:

    Whenever I plug in my external display – which in turn switches on the DGPU – the fans kick in like jet engines running at 6200 rpm. Very loud.

    Switch off the external monitor and go back to the integrated GPU, the fans die down and hover quietly around 2000 rpm as normal.

    Of course, I understand why this happens, but being that my primary usage for this notebook is for recording audio through Logic Studio, it can be VERY irritating. I’ve tried SMCfancontrol and Fan Control to no avail.

    Is there anything that I can tweak to minimize this or is this just par for the course for having a dual GPU system?

    For those of you with the 13” models with only the integrated GPU, do your fans kick up like this when connected to an external monitor?
  2. clickclickw00t macrumors regular

    Jun 28, 2007
    why didn't smcfancontrol work?

    Also, what resolution are you running that external at? Are you playing games on it? Are you using the MBP in conjunction with the external monitor, or are you just using the external with the MBP screen off

    What I do with my external is this:

    Plug in external monitor via MiniDisplayPort
    Plug in mouse, keyboard, and soundcard via USB hub
    Close my MBP lid (external monitor screen should turn off)
    Press a key on my keyboard (wakes MBP from sleep, but with only external monitor on)
    Last step - Open up the MBP lid. The screen of the MBP will still stay off, but you will be able to use your external.

    It is only using GPU for one screen, not two (resulting in less heat)
    Leaving the lid of the MBP open while using an external allows for better air circulation and heat exhaust to come out of the vents.

    I run my external 24inch 1900x1080 monitor and the temps stay @ around 55 idle and 72 load (running Ableton and Logic, 5 VSTs, while at the same time bouncing tracks. As habit, I set my min fan speed in SMCfancontrol to 3500 RPM when I have my external plugged in.

    Let me know if that works for you...
  3. bobthedino macrumors member

    Jan 11, 2006
    I have the stock Apple configuration of the 2011 2.2GHz MBP, and I mostly use it in lid-closed mode connected to an external display... however, when I do this both fans remain at around 2000rpm until I run something that stresses the machine, e.g. the iOS Simulator.

    Are you saying the the fans speed up to 6000rpm just as a result of attaching the external display? That doesn't seem right.
  4. clickclickw00t macrumors regular

    Jun 28, 2007
    Why not run lid-open? I feel like it's much better for the laptop....
  5. bobthedino macrumors member

    Jan 11, 2006
    Yes, I will try this and keep an eye on the temps, thanks. I've heard people say that air can also enter the machine through the keyboard as well as through the intake at the back.
  6. kenmitchell1969 thread starter macrumors newbie


    Jan 29, 2009
    Thanks for the replies.

    I'll try that ClickClick at let you know; I tend to do the same as you for the most part, but more often than not, I keep the MBP on with the external to give me a dual display setup. However, I always thought in that case, the DGPU was handling BOTH the MBP display and the external display, but maybe I was mistaken.

    To answer your earlier question, my external monitor is an old Dell 2005FPW (the same one I used for 5 years with my old Mac Pro) running at a 1680x1050 resolution. I don't play games on the machine at all.
  7. kenmitchell1969 thread starter macrumors newbie


    Jan 29, 2009
    So I think I've found the answer to this wacky problem:

    It looks like the COMBINED temps of the GPU, CPU and Vertex 3 SSD is what makes the fans go nuts. The SSD in particular seems to be the culprit.

    iStat Pro shows the Vertex 3's temperature consistently sitting at 128 degrees. The CPU and GPU look to be normal around 62 & 55 degrees respectively.

    However, when I take out the SSD and put the factory drive back in with the external display and MBP display on, the fans never get beyond 2300 rpm because the stock HDD temp stays in the low 30s.

    But now a strange thing has occurred:

    I put the SSD back in with the external display and MBP display on and now the fans average a much quieter 3700-3900 rpm and go up very slowly. Maybe something got reset with me switching out the drives?

    Go figure... :confused:

    Lesson learned:
    Stuff like this, I believe, is why Apple chooses to only support a couple of specific models of SSD; models that they have fined tuned the performance of right in the OS. They may sacrifice some speed versus some of the 3rd party SSD's, but in the end, the end users would likely not have to deal with issues like this.

    Oh well...Thanks
  8. getz76 macrumors 6502a


    Jun 15, 2009
    Hell, AL
    My Vertex 2 is at 30'C. My Apple SSD in my optical bay is 25'C.

    128'C is a problem. Something is hosed.

    Attached Files:

  9. XandeR803 macrumors member

    Jul 25, 2008
    Just an FYI, the vertex 3 is not actually 128 degrees. I believe it just returns a constant value when queried. You should see that same temp the second you boot up your computer.
  10. WiBu macrumors member

    Aug 10, 2010
    Correct. I have a Vertex 3 and it always reports at 128C for me. I haven't noticed an issue with the fans speeding up during normal use, it only ramps up when I start taxing the GPU/CPU.

Share This Page