GT-AC2900 running at 82°C on Asuswrt-Merlin 386.1 - too hot?

[bumpengrinder]

Firstly to say, I was delighted yesterday to discover the Asuswrt-Merlin 386.1 release for my newish GT-AC2900. I installed like a shot, it's great to be back after months in the stock wildeness. No more ROG theme, what a delightful bonus!

Anyway... after the flash I was having issues with buffering/quality on internet video streaming last night, which I didn't have before, which got me looking at CPU usage & temps. CPU temperature is at around 82°C (ambient 24°C). Is that within realms of okayness?

Last night when I was having the issues, CPU usage seemed to be spiking at 100% every few minutes, which seemed to coincide with the appearance of the buffering circle. In an attempt to fix this I did a "Format JFFS partition at next boot" just now (even though I did do a Factory Default Restore with Intialize ticked after I flashed yesterday, which I believe also formats jffs). That may have improved the buffering & CPU spikes, too early to say for sure, but CPU temp remains the same. Any thoughts on that welcome.

 

[Poncik]

I think 82c is quite warm but still OK. I spent some time trying different fw and currently with RC2-11 41994 my coretemp is ~92c. You might find this post relevant.

https://www.snbforums.com/threads/ac86u-overheats-with-fw-386.70296/

 

[nbdwt73]

My router (AC86U) is on a shelf with open air flow around it. As has been discussed here a lot, the CPU temp is higher on 386.1. Mine was similar (89 - 92). I added two small usb driven fans (https://www.amazon.com/gp/product/B00IJ2J2K0/?tag=snbforums-20 ) - now temp is 50 - 52...

 

[bumpengrinder]

I think 82c is quite warm but still OK. I spent some time trying different fw and currently with RC2-11 41994 my coretemp is ~92c. You might find this post relevant.

https://www.snbforums.com/threads/ac86u-overheats-with-fw-386.70296/

Thanks for that, interesting. It inspired me to switch on SSH and look see if CPU Wait was switched on (it was).

Do you think 386 is simply more demanding on CPU than 384, or does the new code have issues with something specific in the RT-AC86U & GT-AC2900 hardware (which are apparently very similar)?

Having said that, I did not check temperatures before the upgrade (as I did not have any issues) so maybe it was always at 82°C!

Will see how it goes during tonight's binge-viewing.

 

[bumpengrinder]

My router (AC86U) is on a shelf with open air flow around it. As has been discussed here a lot, the CPU temp is higher on 386.1. Mine was similar (89 - 92). I added two small usb driven fans (https://www.amazon.com/gp/product/B00IJ2J2K0/?tag=snbforums-20 ) - now temp is 50 - 52...

Thanks for the suggestion. Is there a consensus then that increased temps on our kit won't be fixed by a future release?

If a fix is not on the cards then I will proably do the fan thing - are the ones you have audible?

 

[nbdwt73]

Cant speak to the temp fix for 86U (I hear that Asus is aware of it). Those fans are very quiet on slow and medium speed. At high speed they are noticeable but low speed is way more that you need to cool this router...

 

[Clark Griswald]

Might I suggest a closed-loop liquid nitrogen cooling system. Keep your router at -350F (approx). No more worries about running too hot.

I never worry about my router temps, yet I checked after installing 386.1.2 and current temp AC86 77C.

Stay Safe

 

[bumpengrinder]

Cant speak to the temp fix for 86U (I hear that Asus is aware of it). Those fans are very quiet on slow and medium speed. At high speed they are noticeable but low speed is way more that you need to cool this router...

Thanks. I'll keep an eye on it. Might get those fans anyway - would be useful in the summer!

Are the one that you linked two fans on one controller, or is it a two pack?

 

[bumpengrinder]

Might I suggest a closed-loop liquid nitrogen cooling system. Keep your router at -350F (approx). No more worries about running too hot.

I never worry about my router temps, yet I checked after installing 386.1.2 and current temp AC86 77C.

Stay Safe

Would that allow me to overclock and get faster download speeds?

 

[nbdwt73]

Those fans are a 2 pack already wired together with a speed control and fit the back of this router perfectly. One other thing to keep in mind. As stated in these forums in several places, routers are designed to run at warm temps. I wouldnt worry about anything 90 or below. However, I have noticed my temps spike when the unit is under heavy load (that seems to happen frequently when VPN tunnels are active).

YMMV but these fans are a cheap insurance policy

 

[bumpengrinder]

Those fans are a 2 pack already wired together with a speed control and fit the back of this router perfectly. One other thing to keep in mind. As stated in these forums in several places, routers are designed to run at warm temps. I wouldnt worry about anything 90 or below. However, I have noticed my temps spike when the unit is under heavy load (that seems to happen frequently when VPN tunnels are active).

YMMV but these fans are a cheap insurance policy

Thanks. Good to know about routers being designed to run warm.

 

[eibgrad]

Just grabbed an old 120mm case fan, soldered a USB connector to it, and rubberband it to my RT-AC68U router. Not pretty but quiet and very effective. Temps dropped from 81C to 56C (lightly loaded). Easy Saturday afternoon project.

https://imgur.com/hfPft8A

 

[ATLga]

Are those of yiu installing these fans having them blow air Into the router or pulling air out of the router. If you’re blowing air in, where is the air escaping? Those little vents on top?

 

[eibgrad]

Are those of yiu installing these fans having them blow air Into the router or pulling air out of the router. If you’re blowing air in, where is the air escaping? Those little vents on top?

At least in my case (RT-AC68U), I'm blowing air in. Notice in the picture there are vent holes exposed on both sides of the fan (they appear a little darker than what's directly above it). There are more below it but harder to see. Across the top are vents too, but they are mostly blocked by internal heatsinks (or shielding). Clearly the fan blowing across that area is having a great effect.

 

[ATLga]

At least in my case (RT-AC68U), I'm blowing air in. Notice in the picture there are vent holes exposed on both sides of the fan (they appear a little darker than what's directly above it). There are more below it but harder to see. Across the top are vents too, but they are mostly blocked by internal heatsinks. Clearly the fan blowing across that area is having a great effect.

Yeah I see the vents on side and top. With such a large portion of the vents covered by the fan, was wondering how much air was escaping (blowing more in than can get out at same velocity). I just wonder if you could achieve the same goal by not having the fan attached to the router and instead put it back a few inches from the backside; that way the air inflow wont overwhelm the ability to flow back out at the same pace.

 

[eibgrad]

I just wonder if you could achieve the same goal by not having the fan attached to the router and instead put it back a few inches from the backside; that way the air inflow wont overwhelm the ability to flow back out at the same pace.

I'm sure you could. It was just easier to attach it directly. I could have wedged something in-between the fan and case I suppose, just to add some room. I even have old fan speed controller I could have used, or even used a resistor. But I just wanted to keep it simple.

 

[r4a]

While attaching fans to routers does lower temps quite effectively, it has one major downside: it fills your router with dust, a LOT dust.
With fan(s) attached you'll have to clean (blow) the dust out of your router at least once per month. You'll have to unmount the fan(s) to do that every time. If that's fine with you, then go for it.
On the other hand, one could experiment with placing the fans on reverse, as in to pull the hot air away from the router, though I'm not sure how effective that would be in terms of cooling but at least that way you could prevent dust building up inside the router.

Otherwise as others pointed out, temps in the range of 70-80C are quite normal.

 

[akamaka]

One other option is to dunk it in some dielectric liquid and only have the antennae sticking out.
Win / win good cooling and no dust.

https://www.3m.com/3M/en_US/data-center-us/applications/immersion-cooling/

 

[bumpengrinder]

While attaching fans to routers does lower temps quite effectively, it has one major downside: it fills your router with dust, a LOT dust.
With fan(s) attached you'll have to clean (blow) the dust out of your router at least once per month. You'll have to unmount the fan(s) to do that every time. If that's fine with you, then go for it.
On the other hand, one could experiment with placing the fans on reverse, as in to pull the hot air away from the router, though I'm not sure how effective that would be in terms of cooling but at least that way you could prevent dust building up inside the router.

Otherwise as others pointed out, temps in the range of 70-80C are quite normal.

Thanks.

75C at the mo. Have been stable since my last post, so will leave it be. if it ain't broke...

 

[bumpengrinder]

One other option is to dunk it in some dielectric liquid and only have the antennae sticking out.
Win / win good cooling and no dust.

https://www.3m.com/3M/en_US/data-center-us/applications/immersion-cooling/

Should I contrive some sort of mechanical swooshing device to make sure the fluid circulates adequately?