$9 Router Cooling (RT-AC68U Example)

[elorimer]

Slightly off point, but the USB ports on my 87U failed over the weekend--nothing would mount. My CPU temp dropped to 40C from 60C.

 

[Ole Geiser]

Is it blowing air in or sucking it out of the router?

Blowing air in.

 

[mattiL]

My solution attached, the colour choice and the little bird is vital to the end result.
CPU temp dropped from 76-77 C to 63-64 C!
A dirt cheap cooler blows air up to the base of the router, I was surprised it worked so well..

 

[martinr]

Following my post above (#33), my cooler arrived. Not immediately suitable for the Asus RT-AC68U because the router has no underside vents, so I removed the 3 fans from the base and snipped out the middle fan.

Not surprising it gets hot: the air vents at the back are tiny and limited. With a couple of dabs of hot melt glue I attached the fans to the back, positioning to try and maximise the air flow in (blowing air in). Even so, perhaps a quarter of the area is blocked.)

And with a couple of filters cut out of cooker-extractor filter paper tacked over the intake - to catch my dead skin cells:

And the bottom line:

Before: 51C 52C 77C

After: 47C 48C 68C

I'm impressed: it comes with a USB passthrough connector, so you don't lose a USB slot to the cooler.

Whether it's necessary is another matter. I just like the pretty blue glow in the corner of the room, and, if the router runs a bit cooler, well, that's the icing on the cake.

It leaves me wondering about all the resources that went into making and shipping the item, all for a mere £3.50 - from the oil to make the plastic, the copper for the wires and the cardboard box it gets packaged in, all for me to rip to bits and slap 2 of the fans on the back of my router, quite probably unnecessarily. Nevertheless, the base, with the spare fan (complete with filter), and an old USB lead, is now giving sterling service as a stand-cooler for my Sony Vaio. A pretty good outcome all round.

 

[martinr]

Following on...... I noticed that my CPU temp, with the 2 fans was 73C (after fitting the fans a few weeks ago it was 68C) So I disassembled the router (RT-AC68U) and improved the thermal coupling of the heatsinks, and added a few extra cooling holes in the rear cover. (Sorry: limited to posting 3 images.)

The rear label is first lifted with a sharp blade and peeled off exposing 2 screws that need to be removed:


Starting in the middle of the bottom edge, the casing is prised outwards to release the tabs on the cover (don't try to prise the cover away: prise the casing outwards and the cover will come off).



Carefully prise apart the 2 sides, again starting in the centre and prising the casing outwards:

Remove 4 screws holding the circuit board to the main casing, and carefully ease out the board.

Remove the heatsink to expose Asus thermal coupling pads:

Check heatsink for flatness and remove high spots with a file and abrasive paper. Undercut the 4 tabs to ensure the heatsink is pulled into contact with the heat sources and doesn't bottom on the 4 screw supports:


Apply thermal paste (I used what is supposedly the best, marginally better than Arctic Silver i.e. not the cheap stuff) - I found it a bit stiff, so I added a couple of drops of solvent to help it spread:

And the last drop for the secondary heatsink. After fixing the heatsinks, a little pressure is applied to squeeze out any excess paste and ensure good contact:

I drilled a few extra holes in the diagonal area of the rear cover where it blocks the airflow from the fans.

The results (room temperature 20C):
2.4GHz 5GHz CPU
Without the fans: 51C 53C 76C
With the fans: 47C 48C 65C



Improving the thermal coupling reduces the temperature of the CPU by around 5 degC, without fans, and by around 7 degC with fans, over the standard ASUS thermal coupling. Whereas, after improving the thermal coupling, the use of the fans pulls the temperature down by some 10 degC over not using the fans, which is what I found previously (earlier in this topic i.e. before using thermal paste).

So we can say the use of fans has a greater effect than the use of thermal paste. And the use of both paste and fans pulls the CPU temp down by some 15 degC. I feel quite sure I could improve on these figures by cutting out 2 holes into the rear cover and by using more powerful fans as proved by the first post in this topic. Nevertheless, for the moment, I think I'll see how it looks in a few weeks' time.

 

[GreGHM]

Interesting discussion. To cool down or not to cool down.
Did anyone experienced burning out of AC68U working constantly with 85-90 deg C CPU temperature?
I'm just curious.
And by the way - found quite interesting fans from AC Infinity (http://www.acinfinity.com/quiet-usb-fans/) did anyone tried specifically these?

 

[martinr]

Interesting discussion. To cool down or not to cool down.
Did anyone experienced burning out of AC68U working constantly with 85-90 deg C CPU temperature?
I'm just curious.
And by the way - found quite interesting fans from AC Infinity (http://www.acinfinity.com/quiet-usb-fans/) did anyone tried specifically these?

I asked a similar question http://www.snbforums.com/threads/high-temp-378-56.27731/#post-212335 and it appears that, on the seemingly very rare ocassions when cpu temperature does cause a problem, the router crashes or freezes rather than burns out. It seems crashing or freezing of the RT-AC68U is so rare that it's plausible some such symptoms might have alternative causes.

 

[System Error Message]

there are other causes such as firmware or bad PSUs. The other thing to know is that temperature is a cause for concern. On some CPUs such as the MIPS, TILERA TILE and such when they go above 70C they start to get very unstable. In the case of the AC68U not only does mean cooler temperatures but it means you can overclock it and everything will work faster since it doesnt use more chips to handle wifi. The wifi chips also need to stay cool because it can cause problems when they get unstable.

 

[ASAT]

I use the AC Infinity dual 120mm fans, fixed to the back of the router with bungee cord. These are 5V DC fans that may be run off the USB power of the router. However, I eventually put them on external power to reduce the load on the router's power supply. At an ambient room temperature of 19C the CPU temperature of the router is 57C. These fans are very quiet. It was gotten on eBay for around $20. To save money you could buy any 5V DC fan and put your own connector on it. Requires solder + soldering iron + heat shrink tubing + heat gun.

If you need more cooling, then try 12V DC fan running on external power. These are quiet too. However, the small AC powered fans are very loud. Walmart is a possible source for small cheap fans, but this may is be seasonal item.

 

[GreGHM]

ASAT thanks for your comment! May I ask you to make a picture how it looks like?
I thought that 2 x 120 mm are too big for AC68U back? No?
I found them accidentally and found them exactly what i need for cooling space around stereo and mediaplayer, and now i have nothing against to put one more behind router.
Can you hear them on Low speed?

 

[ASAT]

I thought that 2 x 120 mm are too big for AC68U back?

You can bungee just about anything to the back of the router. It doesn't need to look pretty. It's not rocket science, it's very easy.

 

[GreGHM]

You can bungee just about anything to the back of the router. It doesn't need to look pretty. It's not rocket science, it's very easy.

you are right! But I am now considering which size i need to buy. Maybe 80 mm fit better? Or one 140 mm? that's why asking about picture - to understand real dimensions comparably to router body.

 

[GreGHM]

just made fast test - i have small 60mm fan from Noctua for PC cases (didn't fit into my old Qnap before), so i made simple usb-connected fan. Same bungeed to back of router gave me in 3 minutes drop down of CPU temperature from 85 to 76 deg C.

 

[Deleted member 22229]

just made fast test - i have small 60mm fan from Noctua for PC cases (didn't fit into my old Qnap before), so i made simple usb-connected fan. Same bungeed to back of router gave me in 3 minutes drop down of CPU temperature from 85 to 76 deg C.

Yep and the Netgear R-7000 has the same hardware and the CPU only runs at 57-59 C with no fan.

 

[GreGHM]

Yep and the Netgear R-7000 has the same hardware and the CPU only runs at 57-59 C with no fan.

To be honest, i don't care. this Asus was running flawlessly even with 85 deg CPU.
Important how it is performing, not how warm or cold it is.
Agree that some Asus hardware developers should be fired after such device design, but that's not our desicion.
If Asus is still happy with them, what can we say?

 

[jerry6]

i run tha fan with a filter over it so it minimizes dust , have to clean filter every 2-3 months . So far temps have dropped at least 8c on 5.2 on my 3200 , ran at 75c now down at 63c wich is reasonable

 

[FlyByWire]

I have installed an BeQuiet 120mm fan to mine RT-AC68U running @1000Mhz dropping temperature from ocer 80°C to below 70C°.

 

[gatorback]

====> UPDATE: http://forums.smallnetbuilder.com/threads/rt-ac68u-wifi-failure.29705/

AC Infinity MULTIFAN S5, Quiet Dual 80mm USB Fan strapped to RT-AC86U

http://www.amazon.com/gp/product/B00IJ2J2K0/?tag=snbforums-20

Would have liked to spend more time to screw the fans in but, it was very quick to zip-tie. Maybe in the future there will be time to 'bolt' it into the router and retire the zip-ties. Effective, but not elegant. UPDATE: I advise against plugging the fan into the USB slot unless you are certain the current drain will not exceed the source's capacity. Fan airflow is toward the router.

 

[jerry6]

Or you could use 2 sided 5lb tape along the 4 sides of the fan to hold it to the router , also acts as a seal so no air leaks from the sides bringing dust , have filters on top of fans to keep things dust free inside router

 

[steven168]

====> UPDATE: http://forums.smallnetbuilder.com/threads/rt-ac68u-wifi-failure.29705/

AC Infinity MULTIFAN S5, Quiet Dual 80mm USB Fan strapped to RT-AC86U

http://www.amazon.com/gp/product/B00IJ2J2K0/?tag=snbforums-20

Would have liked to spend more time to screw the fans in but, it was very quick to zip-tie. Maybe in the future there will be time to 'bolt' it into the router and retire the zip-ties. Effective, but not elegant. UPDATE: I advise against plugging the fan into the USB slot unless you are certain the current drain will not exceed the source's capacity. Fan airflow is toward the router.

why not 2 fan with 1 blow in and 1 blow out?

blow out to blow out the dust inside