SG-3100 - how to reduce it's temp [quietly] ;-)



  • I work in an area of household consumer electronic products where 'higher product temperature means reduced lifetime", so you can imagine my dismay when I saw my SG-3100 running at 65 degrees!!!
    In my sector, that's a no-no. I live in the UK where it's not exactly hot!!!

    The instant fix was this a 40mm usb fan from Amazon. And sure enough the temp of the SG-3100 dropped to 52-55 degrees! Result!!! The speed setting on the usb fan switch was set to medium btw.

    Importantly you need to know that I put the fan below the SG-3100 so that it was sucking air out of the unit through the vents on the underside, and this resulted in a lower temp than if air was blown into the unit...I tried that first. I put small spacers above and below the 40mm fan to give the air somewhere to go.

    So after a while the noise of the fan began to bug me, so I went looking for a quieter option and stumbled upon a YouTube video of a review of quiet pc cooling fans. Thank you @2GuysTek, you told us about the fans....but didn't give a table to compare like with like...so I did.

    Screenshot 2019-10-30 at 20.37.18.png

    And then I looked at the entire Noctura range to get 'the most air-moved for the least noise' fan they offer...I looked for the quietest, and then the next closest which moves the most air, in this case twice as much for 1.5dB more noise (every +3dB is means "twice as loud" btw). BUT at 1/2 fan speed the YouTube guys suggest it's making 8dB...which is seriously quiet.

    Screenshot 2019-10-30 at 20.46.20.png

    Amazon came good again with the Noctura [fan of choice](link url), plus I added this variable voltage regulator and a 15V plug-top psu to the order.

    A bit of wire cutting, soldering, and some little rubber feet later (on both sides of the screw mounting holes of the Noctura) and we're at 49 degrees....and lower noise. Did I mention that the SG-3100 is behind the TV in the living room...

    I hope this helps.


  • Netgate Administrator

    Nice write up!

    That's around the expected running temperature for the CPU though, it runs hotter than other devices. It has been extensively tested in ambient temperatures I would consider insane!
    I still have one of the original prototype boards running 24/7 here, yet to see an issue.

    I won't disagree that cooler is generally better though. 😉

    Steve



  • @stephenw10 - glad you like liked the quick write-up, and it was just that, a fast way to share what might tick a box for another SG-3100 owner with minimal effort.



  • Nice write up! I am still making-do with an itx celeron system, but first sign of an issue and I will be ordering a sg-3100.

    ps 3db isn't twice as loud, Its about the smallest change you would be able to reliably notice. 10db is twice as loud.



  • @pmk_mck
    I have a 120mm fan blowing the side and temps are not as cool as yours. Can you share a picture of your sg3100 with fan?



  • @msf2000 - on my very first attempt to cool the SG-3100 I tried 2x 80mm fans and a very mvp (min viable product) makeshift air-guide to blow air into the side of the unit, but the impact was so unnoticeable that I moved on to cooling from below. I did try also with the fans the other way around to draw off any warm air from the side vents, but that was similarly uneventful.

    To be honest, what I'd love to do, is take the lid off the SG-3100, and pop it onto my CNC, where a little bit of Fusion 360 and a 3mm or 4mm drill bit later would result in about 80-100 perfectly aligned and spaced vent holes in the top of the case. And that's where I'd place the 120mm fan with a grill, and dust filter etc.

    I wonder if anyone on this forum has a dead or surplus SG-3100 with a top cover no longer needed ;-) Though I've seen 3D models of the mechanics of the SG-3100....

    One thing I didn't mention was why I went with a 15v PSU and the variable voltage regulator. Well, my plan is/was to run the fan much lower than it it's full speed, but I couldn't be sure if that would have enough of an impact, so I knew that I'd start testing with the fan running on 12v, but the regulator has a voltage drop of 1.5v, so a 12v psu would have only given me 10.5v due to the voltage drop of the regulator.

    Anyway, here’s a picture of the current as requested, it's still pretty mvp.

    Screenshot 2019-10-31 at 14.03.08.png


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