Solved Sustained Core i7 performance (no throttle) using additional USB fan

Discussion in 'Microsoft Surface Pro 3' started by Daniel Weck, Jan 22, 2015.

  1. Daniel Weck

    Daniel Weck New Member

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    The idea of using some form of external cooling in order to reduce thermal throttling is nothing new. See for example the infamous cbutter's YouTube videos (linked at the bottom of this post) or the "custom fan" discussion thread on this very forum ( http://www.surfaceforums.net/threads/custom-fan-get-more-from-your-sp3.11276/ ).

    However, I have been running some tests using a slightly different approach, so I thought I'd share it here :)

    In a nutshell, here is what the airflow looks like (the USB fan unit is intentionally misplaced, so I could annotate with the blue/red arrows more easily):

    http://s1.postimg.org/7a4u014b1/IMG_1022_edited_arrows.jpg
    [​IMG]

    Note that the vent on the top edge above the webcam is actually an outlet, so we don't want to blow cold air in there!

    In practice, this is how it's used (note how the vertically-stacked fan unit is slightly tilted backwards to match the inclination of the Surface's display):

    http://s1.postimg.org/r26zzbfv1/IMG_1020_edited.jpg
    [​IMG]

    (also note that the fan unit can actually come closer to the tablet, if needed)

    It is important that the fan pulls warm air out from the right hand side of the Surface (i.e. do not blow onto the vent located in the the top-right corner). There is a cold air intake on the top edge of the device, towards the right hand side (you can double-check the airflow direction using a thin flexible strip of paper, and see how it gets pushed or pulled). The main warm-air outlet is on the right edge (towards the top), so the waste flow is sucked into the fan and expelled towards the right. But remember, there is also a hot air exit above the webcam, on the top edge!

    Check out step 9 of the iFixIt teardown, to see where the fan intake actually is: https://www.ifixit.com/Teardown/Microsoft+Surface+Pro+3+Teardown/26595#s66224

    According to my CPU-GPU stress tests using Intel Extreme Tuning Utility, this setup works great: the CPU and GPU can sustain high performance levels for a long time, thanks to the heat levels remaining below the throttling thresholds (which I have not tweaked, by the way ... I have not undervolted anything either).

    Now, what about the lower fan? Well, this one definitely increases the airflow underneath the Surface's flap/stand, horizontally from left to right, along the bottom half of the tablet. This area tends to somehow gather some residual heat too, just not as much as the top-right corner of the device's underside. But every little helps :)

    This silent lightweight dual-fan USB accessory is cheap (7 USD), and whilst it's compact, the fan blades are well-protected for packing / travelling.

    http://s1.postimg.org/un2vijkel/IMG_1021_edited.jpg
    [​IMG]


    PS: I use the USB port on the Surface charger block, so the USB port on the Surface itself is free.

    UPDATE
    Now I have also found a way to "hang" the dual-fan at the back of the Surface (airflow pulled away from the underside, not blowing towards it), which provides plenty of cooling for 90% of my usage (it is also less of an "eye sore", more discrete, in fact I completely forget it is there). The few times I need more "serious" cooling, I just move the unit at the side, as described above.

    http://s23.postimg.org/zcqadsryz/IMG_1026.jpg
    [​IMG]

    Note that I have also tried blowing onto the back using the same configuration, but it only really works when the fans point upwards. Anyway, just run the throttling tests and see what happens :)

    To see more pictures of the fan (folded, expanded), type "usb fan octopus" in Google image search (or click the link below):

    https://www.google.com/search?q=usb+fan+octopus&tbm=isch
    [​IMG]

    [​IMG]

    I bought mine really cheap from eBay: search for "usb fan cool", sort by price (inc. postage), and go down the list until you see one of them. Or alternatively you can add the "octopus" search term, you'll get there quicker but you might miss other model names.

    Some models have a pass-through USB connector ... mine doesn't, but I use the USB socket on the Surface charger...so I'm not too bothered. Still, that's a handy feature if you can get it :)


    [​IMG]

    Full screen (large image):
    http://s24.postimg.org/wtw3efbo5/Surface_Pro3_Corei7_256_GB_Intel_Extreme_Tuning_Utili.png


    I ran a 15-minutes CPU stress test from Intel Extreme Tuning Utility. Max 100% processor frequency is just above 2.8GHz (that's Turbo Boost, the Core i7 4650U being rated at 1.7 GHz).

    The horizontal red line at the bottom of the graph shows how sustained and constant the CPU speed is. The two peaks in the green line at the bottom are minor throttling events that effectively resulted in the internal fan kicking-in, thus why the CPU and GPU temperatures gradually decrease afterwards (blue and green-ish line at the top). During 15 minutes of high load, this kind of (non-disruptive) temporary throttling occurred three times only. Meanwhile, the CPU was running a near-full-frequency.

    When I run Intel XTU's GPU stress test, the CPU stays slow, and the combination of internal + external cooling works as expected (no noticeable degradation in performance). I also tried 3D Mark and PassMark Performance Test ... but to be honest I am not familiar with how relevant these synthetic benchmarks are (all I care about is real-world usage, which in my case does not involve gaming ;) ).

    Anyways, 2855 score at 3DMark Sky Diver (stock CPU settings):
    http://www.3dmark.com/3dm/5629151
    That's with the latest driver for Intel HD Graphics 5000 ==> 10.18.14.4080 (manually installed over Windows' own driver).

    UPDATE:

    Interesting...I noticed that during usage of a demanding 3D city-mapping application (touch-driven, lots of zoom in-out, pan, wide landscape views), the internal fan wasn't pushing lots of heat out through the right edge (normally, primarily the top portion), the underside / back of the tablet wasn't feeling too hot, but the display itself was really warm. I'm talking about the vertical area running alongside the Windows capacitive button, about one third of the total screen width.
    So, I reversed my dual fan unit so that instead of sucking air from the outlet vent, it blows cool air onto the screen. The airflow is indeed quite a bit faster, "sliding" onto the display surface, all the way from right to left.
    Well, that definitely works well too! The internal temperatures went down real quick when I did that. Downside: I don't like typing with a cold airflow on my hands ;)

    LOL (top-bottom airflow)

    http://s11.postimg.org/6k2xyt3v7/IMG_1027_edited_arrows.jpg
    [​IMG]

    http://s13.postimg.org/ygwki4a47/IMG_1028_edited.jpg
    [​IMG]

    Score 2892 :)
    http://www.3dmark.com/3dm/5630235

    External fan blowing from top to bottom, split airflow running along both the back and the glass display ... do not blow air right above the webcam, into the vent on the top edge (this is a warm air outlet)

    --------

    cbutter's YouTube video:
     
    Last edited: Jan 23, 2015
  2. Justing6

    Justing6 New Member

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    Tbh this might be overkill. Your images aren't displaying so I can't analyze your setup, but after using the 3D printed fan from the forum mentioned for a month or so, I have had no problems with it.

    The thing is is that it doesn't really blow any air into the vent at all, for all that was touted in the forum itself. When powered on there may be a SLIGHT breeze through the wing that sits over the SP3's exhaust vents, but definitely nothing that could possibly come close to damaging the internal fan. It also is in no means an airtight seal and I personally don't think removing it would affect its performance at all.

    The actual cooling comes from heat dissipation from the back just like with the arctic USB fan, but in a smaller package without the need to aim it or worry that it something will hit the fan while it is spinning because it is shielded. The heat generated from the processor is transferred through contact from the metal of the Surface to the plastic of the fan assembly, and then the USB fan blowing inside the assembly keeping the unit cool. I'd like to see your setup if you can double check where you liked your images so I can see your setup, as this may be if nothing else a viable cost saving alternative if the mounting is up to par with the unit I use.
     
  3. GreyFox7

    GreyFox7 Super Moderator Staff Member

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    Anything you can do about those missing pictures? Not seeing any of the relevant ones to your post.
     
  4. Cothek

    Cothek Active Member

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    Can you also post some screencaps of XTU showing that you are under the 90C limit. If you are truly preventing throttling as the title suggests then that is a great feat!
     
  5. Daniel Weck

    Daniel Weck New Member

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    Last edited: Jan 23, 2015
  6. malberttoo

    malberttoo Super Moderator Staff Member

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    I like your idea of the lower fan. At those times when my SP3 has been roasty-toasty, I've noticed as you say that when I place my hand beneath the hinge of the kickstand, that I can definitely feel a substantial buildup of heat there too.

    Overall, neat idea and great work!

    AND, welcome to the forum!
     
  7. mohcho

    mohcho Active Member

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    Interesting. Where did you pick that up? Got a link?
     
  8. Daniel Weck

    Daniel Weck New Member

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    To see more pictures of the fan (folded, expanded), type "usb fan octopus" in Google image search (or click the link below):

    https://www.google.com/search?q=usb+fan+octopus&tbm=isch
    [​IMG]

    [​IMG]

    I bought mine really cheap from eBay: search for "usb fan cool", sort by price (inc. postage), and go down the list until you see one of them. Or alternatively you can add the "octopus" search term, you'll get there quicker but you might miss other model names.

    Some models have a pass-through USB connector ... mine doesn't, but I use the USB socket on the Surface charger...so I'm not too bothered. Still, that's a handy feature if you can get it :)
     
  9. Daniel Weck

    Daniel Weck New Member

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    I ran a 15-minutes CPU stress test from Intel Extreme Tuning Utility. Max 100% processor frequency is just above 2.8GHz (that's Turbo Boost, the Core i7 4650U being rated at 1.7 GHz).

    The horizontal red line at the bottom of the graph shows how sustained and constant the CPU speed is. The two peaks in the green line at the bottom are minor throttling events that effectively resulted in the internal fan kicking-in, thus why the CPU and GPU temperatures gradually decrease afterwards (blue and green-ish line at the top). During 15 minutes of high load, this kind of (non-disruptive) temporary throttling occurred three times only. Meanwhile, the CPU was running a near-full-frequency.

    [​IMG]



    When I run Intel XTU's GPU stress test, the CPU stays slow, and the combination of internal + external cooling works as expected (no noticeable degradation in performance). I also tried 3D Mark and PassMark Performance Test ... but to be honest I am not familiar with how relevant these synthetic benchmarks are (all I care about is real-world usage, which in my case does not involve gaming ;) ).

    Anyways, 2892 score at 3DMark Sky Diver (stock CPU settings):
    http://www.3dmark.com/3dm/5630235
    That's with the latest driver for Intel HD Graphics 5000 ==> 10.18.14.4080 (manually installed over Windows' own driver).
     
    Last edited: Jan 23, 2015
  10. GreyFox7

    GreyFox7 Super Moderator Staff Member

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  11. Daniel Weck

    Daniel Weck New Member

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    Interesting...I noticed that during usage of a demanding 3D city-mapping application (touch-driven, lots of zoom in-out, pan, wide landscape views), the internal fan wasn't pushing lots of heat out through the right edge (normally, primarily the top portion), the underside / back of the tablet wasn't feeling too hot, but the display itself was really warm. I'm talking about the vertical area running alongside the Windows capacitive button, about one third of the total screen width.
    So, I reversed my dual fan unit so that instead of sucking air from the outlet vent, it blows cool air onto the screen. The airflow is indeed quite a bit faster, "sliding" onto the display surface, all the way from right to left.
    Well, that definitely works well too! The internal temperatures went down real quick when I did that. Downside: I don't like typing with a cold airflow on my hands ;)
     
  12. GreyFox7

    GreyFox7 Super Moderator Staff Member

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    :) I once had an office in the back of the computer room... typically 60F/15.5C degrees in there... but we were tough :)
     

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