Router temperatures

[AntonK]

I guarantee you, it is related to the firmware.
We know of a very specific set of changes that were made that contribute to the worst of the temperature increases, namely the CPU Wait and EEE settings.
The remainder is something deeper, and probably AIMesh related.

You are right though that it is also absolutely hardware related. Some units have poorly fitted heatsinks, and there doesn't seem to be any pattern in manufacturing dates that anyone can discern yet.

Having disassembled the router, users are seeing those extra thick thermal pads. These are likely the cause, as thermal transfer through such a thick pad is going to be sketchy and unpredictable.

In short, the firmware change, has made an underlying hardware issue more prominent for some ac86u owners. Everyone will see a small temperature increase, but those with dodgy heatsinks will see a larger increase.

In my own case, the temps were pushed beyond 100 degrees, and the CPU started shutting down cores.

Is this confined largely, or solely to the RT-AC86U model?

 

[Wade Coxon]

Is this confined largely, or solely to the RT-AC86U model?

It is primarily on the ac86u.

Owners of other routers have also reported higher temps, but they are in a minority AFAIK.

 

[CaptnDanLKW]

I did an extensive test around the effects of Energy Efficient Ethernet (EEE) back some pages back in this thread.

Its been a few days since I posted it. I'm seeing a -10C difference (79C vs. 89C) with EEE on and all 4 ports in use at 1GBps. I don't have negative effects from turning this on. With the CPU Wait fix some time back + EEE enabled my 386.1_2 temps are within same range as 384.19.

Router temperatures

Okay, I get that this thread is separated out from the beta as just noise. This thread is just about the 86U. This thread is just about the changes some see in .2B, and I assume not because of anything to do with the Merlin beta, but perhaps something new in the GPL we are first seeing in the...

www.snbforums.com

I did restart my router yesterday and when I checked the temp this morning I remembered I never put the command in a startup script when I saw 89C.

When the command (/bin/pwr config --eee on) is executed, it bounces all 5 ethernet ports, so I'm looking for advice on which script it should run in.

I'm thinking init-start since the switch bounce will cause a wan bounce, which could cause issues with other startup sequences. Thoughts?

 

[Wade Coxon]

I'm thinking init-start since the switch bounce will cause a wan bounce, which could cause issues with other startup sequences. Thoughts?

I have been using services-start without any issues, though init-start is probably a better idea. I might change mine to that.

 

[gattaca]

I have been using services-start without any issues, though init-start is probably a better idea. I might change mine to that.

I've been using /jffs/scripts/services-start I just guessed that might be best b/c IDK the full order start order or where ASUS may be flipping them to what they wanted... I cannot play with this until the family's eyes are closed..

 

[GHog]

All electronics can have heat issues. If you remove covers on ASUS routers you will see that the heatsink could be larger, but the cases air vents and position of the heatsink does not help remove heat. Short story is the natural chimney convection that is needed to remove heat just does not work well on most ASUS routers. This is their weak point, but easing with circulation is helped with fans. So with that in mind, just fix the problem. With an RT-AC68U style of router/case this cooling fan works great and you can keep temps down in the 50 and lower range.
https://www.amazon.com/dp/B07FSKQWCZ/?tag=snbforums-20

For my RT-AX88U I use a cooling plate from AC Infinity. I built a stand to hold cooling plate and then place my router on top of it. Temps stay in the 40`s range. Also get the foam filters for the fans to keep dust out of the router.
https://www.amazon.com/dp/B009CO543S/?tag=snbforums-20

Here the thing we must remember. As firmware is modified and cpu`s are performing more work we get more heat. Also by adding fan cooling, it keeps radio`s temp lower and they are more stable and I am sure this will reduce drop out issues others are experiencing. I never have radio or router issues when using cooling fans.

Just get some fans and add to your routers. Use that old cell phone ac adapter if you do not want to use usb jacks on routers.
Here is a couple of pics of my RT-AX88U setup and temps. Room temp where this router is located is 70F. I am a woodworker so I have the tools to make my stand from wood. Since my RT-AC68U is the node for my mesh setup, I cannot get to the temp graph. It also has similar temps.

 

[WillyTP]

Hello everybody.
Today I've made the hardware mod and closed the router.

The following picture speaks more than words:

In a very few words:

• I changed all the termal pads, with ARCTIC 1,5mm ones. When necessary I used just the 1,5mm one, otherwise two stripes of 1,5mm for a total of 3mm
• Solely for the CPU, 1,5mm copper pad + 1,5mm thermal pad.

In my opinion RF ICs temps could be even better if I used some copper even there.

Hence, IMHO, all these temperature issues are an hardware problem.

Thanks

 

[teo1966]

That's still not quite how Ohm's law works.

Remember that W = I^2 x R

Adding resistance will increase power linearly, but the resultant drop in current will reduce power by the square of the current. Adding resistance to a fixed voltage circuit ultimately reduces the power and heat generation because the current falls.

Similarly, lowering the voltage drops the current (into a purely resistive load) and thus the power and heat.

here is a site to calculator your weerstand ( its in dutch )

Ventilator voorschakelweerstand Calculator - Faq.tweakers.net > Casemodding & Elektronica

 

[RMerlin]

I don`t want to get re-involved in this long, old discussion, but just to put the facts in one location:

- The router will start disabling CPU cores if the temperature reaches 100C. So no, it won`t burn itself out overnight, Broadcom has thermal management implemented. Core shutdowns will be logged in the System Log.
- In the initial 386 release, Asus disabled the CPU Wait instruction on the RT-AC86U, which led to a significant temperature increase. It was done at the recommendation of the CPU manufacturer to address a specific issue (no, I don`t know what that issue was), not just because they wanted to annoy their customers (so, take down those tin foil hats)
- Since it was causing some people to hit that 100C limit, Asus has since re-enabled support for the CPU Wait instructions on that model.
- My firmware has always had it enabled in official releases, only alpha/beta builds had it disabled for a while.
- Anything between 65 and 85C is perfectly normal for that CPU. Other models with a similar CPU also tend to run at around that temperature. It's what it was designed to operate at.
- If YOUR router is hitting 95-100C right now, you have an airflow issue, or a hardware issue, as other people with the exact same router model are running it at around 80C. Make sure you provide adequate cooling (don`t put it on top of a cable modem within a closed cabinet!). If it does get sufficient airflow, then your router has a hardware problem, most likely related to poor thermal contact between the heatsink and the CPU.

 

[MvW]

here is a site to calculator your weerstand ( its in dutch )

Ventilator voorschakelweerstand Calculator - Faq.tweakers.net > Casemodding & Elektronica

Your weerstand = resistance. Here it's in English, using Google Translate: https://translate.google.com/transl...ttps://faq.tweakers.net/cme/fanweerstand.html

 

[Tech9]

Anything between 65 and 85C is perfectly normal for that CPU.

Not at close to idle conditions. I see you have a new PC with Ryzen 9 CPU and the maximum temperature for this CPU is 90C. Does it run at 65C idle in your computer? Of course it doesn't because you expect the full performance available when you need it. What Asus did with those routers is clearly cutting corners. They saved less than $2 on a router with $200 initial price. Machining a heatsink or using copper is expensive and not needed. Three 1 cm2 aluminum pieces solve the overheating issue permanently. The decision to slap 3mm thick thermal transfer pads was made by someone with degree in economics, not electronics.

 

[Tech9]

I guarantee you, it is related to the firmware.

The routers were working close to the edge with previous firmware versions. A bit more CPU load in 386 version triggers the issue. Run a test software like Prime95 on your computer. If you see it overheating and throttling cores where is the issue - in the software or somewhere inside your PC case? Folks above report 80C in a 15-20C room and call it normal. Guys in tropical countries may have >30C ambient temperature. They will be running >90C doing exactly the same things on their routers. Where is the CPU temperature going with 40C ambient temperature? Remember, operating temperature 0-40C in the user manual.

 

[Tech9]

but the cases air vents and position of the heatsink does not help remove heat

The looks are important. The average customer has no idea what's inside and what it does. Cut one of the Asus original 15cm long antennas and you'll find a 5cm actual antenna inside. Longer and thicker antennas make the router look more powerful. Red accents or RGB lights make the router look more gaming. Later some curious realize the cheaper AC86U with the help of RMerlin can do more than AC2900 with standard Asuswrt and RGB lights.

 

[Wade Coxon]

The routers were working close to the edge with previous firmware versions. A bit more CPU load in 386 version triggers the issue.

Did you read my next paragraph?
I literally said that the preexisting hardware thermal management issues were the reason for the overheating.

However I am also not wrong that the new firmware is an absolute contributor to pushing the routers over the edge.

Hence the issue *is* firmware related. Just because that is only part of the story doesn't mean the firmware didn't contribute.

 

[RMerlin]

Does it run at 65C idle in your computer?

Close, very light load (such has one background VM, a Shoutcast stream playing, etc...) sits at around 55-57C on average. But I fail to see why you are comparing a 7nm CPU with a 28 nm complete SoC.

Not at close to idle conditions.

Uh, it is, unless you can show me spec sheets that say otherwise. Those CPUs have been running at these temperatures for years, both in Netgear and Asus products. They have Tjmax at 120C, and will shut down cores at 100C. That`s like 20-35C of headroom to spare before core shutdowns, and 40-55C of headroom before damage.

 

[alex1236hk]

guessing they are going to release a "AC86U B1" to fix that issue
if it can't be fixed with firmware

 

[Tech9]

Close, very light load (such has one background VM, a Shoutcast stream playing, etc...) sits at around 55-57C on average.

Only because you want it quiet. When you load the CPU the fan speeds up to increase the airflow. Routers don't have that option.

 

[goodwin_c]

Close, very light load (such has one background VM, a Shoutcast stream playing, etc...) sits at around 55-57C on average. But I fail to see why you are comparing a 7nm CPU with a 28 nm complete SoC.


Uh, it is, unless you can show me spec sheets that say otherwise. Those CPUs have been running at these temperatures for years, both in Netgear and Asus products. They have Tjmax at 120C, and will shut down cores at 100C. That`s like 20-35C of headroom to spare before core shutdowns, and 40-55C of headroom before damage.

Usually, these SoCs are not afraid of high temperature (as you said - they have thermal management with protection), so that's not a case. And I'm almost sure that you'll never find any Asus router with the dead by overheat CPU or Radio. However, you will find some semi-dead or fully dead router. And that's because of heat Problem is that high temperature in highest points and then natural cooling is destroying soldering points under the MCUs, and that's a fact. And the problem is mostly in Pb-free solder, that "green" companies are using (I hate when the marketing department is doing devices, not engineers). For Asus routers it is common to have an issue with, for ex., one side Radio (2.4 or 5), or with no operation (non working CPU) - I was able to see a lot of such routers on eBay and other places. And almost all this happened because of bad thermal design.

 

[CaptnDanLKW]

I don`t want to get re-involved in this long, old discussion, but just to put the facts in one location:

- The router will start disabling CPU cores if the temperature reaches 100C. So no, it won`t burn itself out overnight, Broadcom has thermal management implemented. Core shutdowns will be logged in the System Log.
- In the initial 386 release, Asus disabled the CPU Wait instruction on the RT-AC86U, which led to a significant temperature increase. It was done at the recommendation of the CPU manufacturer to address a specific issue (no, I don`t know what that issue was), not just because they wanted to annoy their customers (so, take down those tin foil hats)
- Since it was causing some people to hit that 100C limit, Asus has since re-enabled support for the CPU Wait instructions on that model.
- My firmware has always had it enabled in official releases, only alpha/beta builds had it disabled for a while.
- Anything between 65 and 85C is perfectly normal for that CPU. Other models with a similar CPU also tend to run at around that temperature. It's what it was designed to operate at.
- If YOUR router is hitting 95-100C right now, you have an airflow issue, or a hardware issue, as other people with the exact same router model are running it at around 80C. Make sure you provide adequate cooling (don`t put it on top of a cable modem within a closed cabinet!). If it does get sufficient airflow, then your router has a hardware problem, most likely related to poor thermal contact between the heatsink and the CPU.

@RMerlin
Just to add one more (RT-AC86U) item to the facts list. Each LAN port, when device connected is at 1GB, adds ~4-5C increase when EEE is off (the default). Tested on two fresh rebuilds, M & M with no add-ons; a very old 2017 unit and a slightly newer 2018 unit with the same result.

We can easily overlook our wired connections as we try to figure out 'what changed'. Honestly I only recently stumbled into this thought process on Monday morning when mine was back up at 91C after it was running at 81 all weekend. I had that 'ah-ha' moment when I realized it was the start of a new week and I had recently powered up my 2 work laptops & docking stations.

As always, YMMV but I've found something that makes a significant difference.

 

[capncybo]

My 2bits... Hot air rises + my Asus router was always somewhat jealous of the cool looks of a Nighthawk.
With this mod I combined aesthetics & performance...

Edit: It even supports LED-Off Mode (But not LED-ON ;-)