Router temperatures

[WillyTP]

Morning. Please post your results. Not having the screws tightened points to a marginal assembly process and if there's not excellent contact even with those pads, heat transfer is way impacted. I've not opened my AC86U or AX86U units b/c I usually sell them when I waterfall them outta the setup and use the Noctua fans. If you have tips on disassembly or a post, that would be cool b/c I have one of the AC86U offline right now and could open it to check out those 3-4mm pads! Yikes - a build assembly and too high tolerance factory assembly compromise?

I've to adjust my previous post: after some hours being on, temperature raised to 76°c (remember: router without cover now)
However, still a great result compared to the previous 96°c.

In order to "make it easy" and cheap (non-sense spending more in modding rather than changing the router...)
I've found and bought a 1,5mm copper cushions and some 1,5mm branded thermal pad.

Once done the mod I'll post the definitive results.

 

[clweb]

^^^ That certainly is atypical of every router I've owned. I've never seen the 2.4GHz radio be hotter than the pCPUS. I don't own that model though. Have you verified nothing is blocking any vents (not trying to be a smarta$$) ? If all good, then I'd suspect a thermal pad is missing or maybe dislodged or all of the above discussions. The chips will slowdown/idle to protect themselves typically. That graph seems very odd.

Yes I was thinking about a hardware problem (thermal pads), but it did never happen with Merlin 384.19 and these 76°C are also strange. But I will take a look inside.

 

[Tech9]

I see where and how any copper shimming would have to work.

The place is very tight. I had to cut some copper to make it fit there. I believe the RF ICs gap is about 2.4mm and the CPU gap is about 2.8mm. It was months ago and I don't remember the exact dimensions. Clean the silicone liquid before you apply the thermal paste otherwise it won't stick to the ICs. Be very careful when removing the back side heatsink. This one comes off first and there are multiple thermal pads underneath. If you damage them you'll have to find a replacement. You'll find multiple greasy spots on the PCB around the thermal transfer pads. A larger spot under same size thermal transfer pads indicates warmer component. The burned step down converters had 1 inch spots around them.

 

[Maverickcdn]

Unless someone is going to spreadsheet router models/average temps/ambients/percieved air flows/# lanclients/avg throughput and importantly CFE versions this thread will be going in circles.

86u mod
HND CPU temp monitoring

 

[WillyTP]

The place is very tight. I had to cut some copper to make it fit there. I believe the RF ICs gap is about 2.4mm and the CPU gap is about 2.8mm. It was months ago and I don't remember the exact dimensions. Clean the silicone liquid before you apply the thermal paste otherwise it won't stick to the ICs. Be very careful when removing the back side heatsink. This one comes off first and there are multiple thermal pads underneath. If you damage them you'll have to find a replacement. You'll find multiple greasy spots on the PCB around the thermal transfer pads. A larger spot under same size thermal transfer pads indicates warmer component. The burned step down converters had 1 inch spots around them.

I measured this morning.

CPU gap 16x16mm, RF ICs 13x12mm.

Thanks

 

[AntonK]

It seems clear now that a value-added benefit of owning a number of models of ASUS routers is that you get an intensive immersion course in eletronic component thermal management. Very nice if you're a lifelong learner!

 

[Tech9]

86u mod

The real issue in pictures. Very nice, thank you!

 

[heysoundude]

My advice is don't use compressed gas. Evaporating process takes away heat rapidly down to subzero temperatures. Thermal stress points are the weakness of RT-AC86U. You may kill the router this way. I mentioned above reflowing components due to micro cracks in BGA solder. Larger PCBs expand more. Spraying one end of the PCB may kill a component somewhere in the middle of it. RF ICs are close to the middle of RT-AC86U PCB. Brush off the dust and use the router until it lasts. It's a good performing router when it works.

I wouldn't do (and haven't done) it when it was energized or warm. I turn it off every 6 mo or so to let it cool down completely overnight and then blow it out before re-powering it.
these power and heat cycles is what shortens every electronic piece's lifespan, I agree.

 

[heysoundude]

I've to adjust my previous post: after some hours being on, temperature raised to 76°c (remember: router without cover now)
However, still a great result compared to the previous 96°c.

a 20C drop in temp is not insignificant.
has anyone considered drilling cooling holes in the front of their AC86, I wonder?? more holes for heat to dissipate naturally...
adding a fan would only help drop it more.
these are macintosh apples to granny smith apples comparisons:
my raspi4 ran in the mid 60C range - fan addition dropped it into the 40s. had to take it out of the case for the fan, but blowing air across the chips had to be done. (I havent attempted overclockingg it or the GPU, but it's possible)

 

[MvW]

Ladies & gents,

I think it's save to say my fans have arrived. I decided to use the ones with dust covers. The temperature difference is huge. 34 Degrees Celcius within a little under 20 minutes of use.

But the noise, that'll really take me some time to get use to...

 

[Sky1111]

@Tech9 , any thoughts on AX86u?
Is it as poorly (or deliberately - agreed with all your points) designed as AC86u?

P.S. found this: https://fccid.io/MSQ-RTAXI600/Internal-Photos/Internal-Photos-4616819

 

[Tech9]

@Tech9 , any thoughts on AX86u?

No, sorry. It's a new model router still under warranty. I don't expect to see it for recycling any soon. I have one dead RT-AC5300.

 

[Tech9]

P.S. found this: https://fccid.io/MSQ-RTAXI600/Internal-Photos/Internal-Photos-4616819

Very similar design. Different type of thermal transfer pads gray in color. AC86U has very soft pink pads inside. A change in material type and quality makes a difference. I can't say much just looking at low resolution pictures. Perhaps Asus addressed the issue. A replacement option for failed AC86Us.

 

[Sky1111]

AX86u does run very hot with new FW, and on the main router I have 120mm 12v fan running very quietly from onboard USB port (please do not shoot me, I know it is not kosher to do so; I did use ferrite choke on that short USB cable).
With said fan blowing directly on the router, but not attached to it, my temps are very reasonable: typically 64C, the range is 62-65 (never more than 65, even under load)
the node one I have no idea, perhaps should get another fan...

 

[Wistuplu]

Hello All,

Thank you very much for the ideas of solutions.

I don't want to imply that the issue doesn't exist but I'd like to illustrate that it's not universal.

****************************
Legend: 2.4 GHz - 5 GHz - CPU
Current Temperatures: 46 °C - 49 °C - 74 °C
***************************

AC86U, no mod, no fan., 20°C ambient temperature
386.2 Beta 1, 125Mbps down and 7 up, not much traffic, built-in cake active,
just one cable plugged in the 4 port built-in switch (linking to an external 8-port switch)

I guess the actual traffic, bandwidth, scripts might also impact the temperature.

Good luck
Regards
W.

 

[Il vient]

With this fan kit bundle for $25.99, the temperature of the RT-AX88U dropped from 77ºC to 54ºC degrees (room temperature between 27ºC to 33ºC degrees).

Amazon:

• AC Infinity MULTIFAN S7-P, Quiet Dual 120mm AC-Powered Fan with Speed Control.

Amazon Images:

Bottom of the RT-AX88U:

 

[juniorsweet]

Thanks for starting this thread and thanks to the many folks who have commented with helpful insight, ideas, and thoughts.

In the hopes that more observations will be helpful, I wanted to share temperatures from my RT-AC86U before and after adding a cheap external fan I purchased from amazon: https://www.amazon.com/gp/product/B07XDGXWC3/?tag=snbforums-20

My biggest concern in purchasing this fan was that it would be too loud. The unit I bought has a knob that adjusts the fan speed. I currently have it at about the 50% mark and the noise is barely perceptible. Based on the 15-20°C reduction in CPU temps I've seen, I have been very happy with the results.

384.19 temps 51 57 72 °C
386.1_2 temps 52 57 77 °C (no fan)
386.1_2 temps 45 52 59 °C (with fan)

*Edit to add that I am using 3 of the 4 available LAN ports.

 

[MvW]

I don't want to imply that the issue doesn't exist but I'd like to illustrate that it's not universal.

That would be even kinda hard looking at the graph I posted above

We have some similarities in our setup: I also have a DOCSIS 3.0 Cable modem from my ISP in bridged mode. I have a 250/25 Mbit connection and the local distribution cabinet which connects to one of the local backbones is literally 6 feet away from my indoor connection. My network is rarely under a heavy load. Basically never actually.

My son is still partly having his school through Google meet at home, he plays some games during the second half of the afternoon, I watch streaming content during the evenings, no heavy duty tasks for me during daytime, nothing out of the ordinary. Nothing that would justify these temperatures. I do have all 4 LAN ports in use. As for the LAN-ports: one is used for a 100Mbit connection to a Philips Hue Bridge on a safe distance which, just like the router, needs to be at a central place in our home so all the Philips Hue equipment is within reach. Two of the LAN ports are used for two 8-port managed switches, one in the living room, one in my kids bedroom and the last LAN-port is used for the ethernet backhaul to the RT-AC68U which is placed on a high cabinet in my kids bedroom. Because of the strange construction of our apartment (I literally have an outer, concrete wall built over 1 meter (close to 4 ft) in length into our living room, in our tiny apartment), blocking all signals to the other side of our L-shaped 50 square meter apartment. This is the only way I can get a decent signal in all rooms.

I expect a device with one WAN port and 4 LAN ports and two USB ports, of which one of them is a USB 3.0 port, to have a build quality, capable of offering all connections mentioned before and still function at a reasonable temperature. I don't feel 94 degrees celcius for a router, that's mostly idle, is reasonable. And it varies between firmware releases, that's why I think it's justified to say that besides poor build quality the software is showing flaws. But I'm not allowed to use the word bug, therefore my posts got moved here from the beta thread as I was causing 'noise'. You know what's causing noise? The two darn fans I had to mount on the back of a router I purchased for 249 euros at the time of release.

Before I made the switch to Asus (which I did specifically to be able to use Asuswrt-Merlin) I used only Netgear. Never had any issues whatsoever and I owned a broad range of models, extenders and the lots. Never regretted the switch until the temperatures started to rise. If one supplies a router in this range with four LAN-ports, the buyer should be able to use them, without getting temperature issues.

Just my two cents. And two noisy fans, too.

Best regards,
Marco

 

[gattaca]

^^^^ AC Infinity usually makes good quality fans. Those are double-ball-bearing which are quieter than sleeves and that is a good price for 2 fans plus the PSU. I guess they are missing a whole market for ASUS router fans. That looks like a good bake and will do nicely! I never went there b/c I had the Noctuas sitting around already. Thanks for sharing the info!!

 

[MvW]

I guess I'll have to be on the lookout for something similar. This was nice to try for 14 euros (around 17 bucks) but the noise is unbearable now the whole house is quiet. At least it has proven it can lower the temperature close to 40 degrees Celcius (94 without, 55 now with fans, albeit the ambient temp has also slightly decreased) but I definitely need some better, more quiet fans before these drive me nuts).