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DSL AC68U temperature

Discussion in 'Asuswrt-Merlin' started by GNUton, Jun 11, 2019.

  1. GNUton

    GNUton Regular Contributor

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    Hi,
    Do you have a DSL AC68U? What s the temperature of your device? When in idle the CPU temperature is around 80C for me.

    Sent from my Pixel using Tapatalk
     
  2. L&LD

    L&LD Part of the Furniture

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    Yes, same as for the RT-AC68U too. :)
     
  3. skeal

    skeal Part of the Furniture

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    All you need to do is blow air at it and it will come down. Some have used laptop coolers some CPU fans etc. or just blowing air at it with a table top fan. Very cheap fixes. This temperature you have now is the usual.
     
  4. skeal

    skeal Part of the Furniture

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    If you do add a cooler of some sort or fan, don't use the usb port on the router to power it. If the fan fails it could take your usb bus down.
     
    martinr likes this.
  5. L&LD

    L&LD Part of the Furniture

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    He's asking what the temp is, not how to cool it. :)
     
  6. RMerlin

    RMerlin Super Moderator

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    Reminds me of a tech vs engineer joke...

    An engineer and a tech are looking at a utility pole. The engineer wonders the height of the pole. The tech suggesst putting down the pole, and measuring it. The engineer's answer:

    "You friggin' techs, I ask you for the height, and you want to give me the length!"
     
    royarcher, Makaveli, isr25 and 8 others like this.
  7. Swistheater

    Swistheater Very Senior Member

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    my regular ac 68u's are idling nicely at 75 degrees even the new rev. one with the faster processor.
    note: lowest i have seen is 70 due to me adjusting down some of the power save features.
     
  8. Swistheater

    Swistheater Very Senior Member

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    [​IMG]
     
  9. martinr

    martinr Part of the Furniture

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    My RT-AC68U is showing 66C. But it’s a cold day. It has been as high as yours in the summer.

    This topic comes up every few weeks.

    I experimented, because I had nothing better to do, with thermal paste and cooling fans. And afterwards when I got my spare RT-AC68U, I never even bothered with the thermal paste, having decided the temperatures we see have no discernible detrimental effect.

    Eg

    https://www.snbforums.com/threads/9-router-cooling-rt-ac68u-example.26733/

    If you search in the forum for cooling fan, you should get loads of hits, if you have nothing more interesting to do! Otherwise just forget about it, I’d suggest.
     
    Swistheater likes this.
  10. Ian72

    Ian72 Occasional Visitor

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    This is the reason I also asked about temps,until I put a usb fan I'd bought behind the router it was at 89c with only 4 devices connected and very low cpu use.
    It's at 62c atm and hopefully might drop some more,as I gather later when it's under higher use the temp would have been higher.

    I'm just bothered why mine was at 89 in the first place when someone else in the Uk on a cold day has temp at 66
     
  11. martinr

    martinr Part of the Furniture

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    Using an infrared thermometer, I just checked my router. It’s stood on top of a DVR, which is giving a reading of 29C, and the router casing is showing 33C. Might be a cold day, but it’s fairly warm where the router is! My cpu temp is still showing 66C, and the router is doing nothing at present other than whatever it does in the background. (Both cpu cores are averaging less than 10%.). That probably muddies the water rather than clears it.
     
  12. Ian72

    Ian72 Occasional Visitor

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    Well mine is at the back of my desk not next to a wall or anything,although the modem is next to it.

    Although the modem doesn't feel warm, as I said without the fan the temp was 89,just seems odd mine is so much warmer without the fan.
     
  13. martinr

    martinr Part of the Furniture

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    And to muddy the waters even more, my original RT-AC68U router is in my garage as a spare. I decided to turn it on and see what temperatures immediately register.

    So with the router at 13C (summer day in England), I turned it on. As soon as it had booted I logged in. The temperatures shown (2.4GHz, 5GHz and cpu) were 34, 36, 42.

    After 5 mins they were: 36, 38, 43.

    After over 20mins: 36, 38, 44.

    That suggests to me that the cpu temp did not jump from 13C to 42C in the minute or so it took to boot up.

    It leaves me wondering how accurate the temperature measurement is.

    If it were worth it, I would remove the back and the heat sink and attempt to measure the cpu temp with my infrared gun very close up. I might also, if there was room in the freezer, have put the router in there for an hour to see what the webui temperature reads on boot-up. Maybe a better test would be to stick it in an oven for an hour at say 80C and then see what the boot-up temperature reads.

    For now I’ll just throw another variable into the equation and say it’s possible there might be some inaccuracies in the temperature readings. On the other hand, it might be that only at low temperatures, outside the normal envelope, the readings can’t be trusted.

    But I’m still of the opinion it’s not worth worrying about. If we didn’t have that temperature readout in the webui, I doubt anyone would ever post to say their router felt warmer than expected. And I don’t believe anyone has seen a correlation between router gremlins (or failure) and very hot weather. In fact, you’d have to search hard to find any mention of gremlins in the AC68U, well, gremlins of the non-user-generated variety, and even those seem few and far between.

    I vote for Merlin removing that temperature data so we can settle down to blissful ignorance. ;)
     
  14. Ian72

    Ian72 Occasional Visitor

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    Thanks for the info anyway,I'll guess I'll leave the fan on I bought it certainly can't do any harm.
     
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  15. ColinTaylor

    ColinTaylor Part of the Furniture

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    I don't see why that couldn't be the case. Same as with my PC, if I turn that on an enter the BIOS as quickly as possible the CPU has already plateaued at 35 degrees, and that's with a massive fan on it. Bear in mind that these are die temperatures and not the external temperature of the chip carrier, so the temperature rise from ambient is very fast.
     
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  16. martinr

    martinr Part of the Furniture

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    That’s good to know. I was thinking that with such a large heatsink, which would still be close to 13C one minute after switching on, there’d be more evidence of a rise in cpu temperature over the following 5 minutes or so.

    So the jump from 13C to a relatively stable 42C within a minute of switching on suggests to me the point of measurement is a tiny source deep inside the cpu, and that a final temperature of 80~90C at the same point is a long way from the 1400C melting point of silicon. That convinces me even more that there is nothing serious to fret over.
     
  17. Grisu

    Grisu Part of the Furniture

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    As I often said there are many RT-AC68U which are not well buildt with a gap between shielding metal and the large heat sink!
    Chip has a small thermal pad to the shielding and another larger pad to the heatsink. And the screws are only on the edges while it is bent up in the middle.
    Temps are mostly stable after 5-10 min and may raise 5°C more after 30-60 minutes positioned on an open place.
    And the values are very accurate as measured on the chip!

    Even with removed heat sink I had "only" 85-90°C with an open housing.
    And thats the point!!!
    If that would be ok they could build them without heatsink at all!
    And those seeing such temps on their router will get a problem someday ... or luckily replace it before
     
    Last edited: Jun 12, 2019
  18. martinr

    martinr Part of the Furniture

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    Yes those pads - like double-sided sticky pads - are horrible. On my original touter I got rid of them and put thermal paste between the cpu and the heatsink. I think that brought down the indicated temp by around 5 degC.
     
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  19. Zendilar

    Zendilar Occasional Visitor

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  20. heysoundude

    heysoundude Senior Member

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    Thermoelectric cooling between the CPU and heatsink, thermal paste gluing them together:

    fans to blow air across the heatsink would help too.