Am not really sure i understand your concern about the 70C… Are there any evidence that this temperature can harm the device ?
Or does 70C is concidered a high temperature for CPU ?
If you put a FAN and the temp goes down to 10C does that mean your device will run better or something else ?
I must admit I’m indeed a little bit concerned b/c with a CPU load of below 1% it shouldn’t become so hot, IMHO…
My primary concern is, as already said, when I later fully populate the device (ie. 2 SFP+ plus 24 Gigabit ports)…
My desktop and laptop quad core beasts have idle temps of about only 38C in normal room environment.
You know better…
Tested ambient temperature range is temperature in which device can be physically located. It is not the same as cpu-temperature.
For CRS devices, with passive cooling, such temperature is completely normal and while device is located in environment where temperature do not exceed mentioned temperature in device specification, there is nothing you should be worried about. If you still think whether it’s not too high, you can always contact MikroTik support.
For this particular device there is no option to add an active cooling fan/fans. If you want to cool down its temperature, you have to consider to use other active cooling sources.
Too bad that MikroTik does not have such an add-on accessory solution for these classes of their products.
But is it possible to get power from the board for a cooling fan, either from the board or from one of the RJ-45 ports, or from the console port?
The other alternative would require an extra power supply, which I rather would avoid if possible.
Thx
The concept is very creative, but in a “real world” deployment it would be a nightmare to cable.
@mutluit as you can see from the previous post, @Elans who is from Mikrotik Support, said that the temperature is normal…
Why do you insist that it is not normal ?
This high idle temperature of 74C cannot be normal IMHO, believe me 
. I’m not the only one who sees it that way. Many people think that the idle temperature
of this device is by far not normal. Either the passive cooler (the heatsink) is not sufficient or is misdimensioned, or something else is wrong with the device CPU regarding that high heat.
Cf. also the link in the previous postings above, ie. http://forum.mikrotik.com/t/crs326-24g-2s-rm-fans/111316/1
and here in the following external article are some more temperature-related comments below the article
https://www.servethehome.com/mikrotik-crs326-24g-2srm-review-inexpensive-24-port-1gbe-switch/ :
Adhidarma Hadiwinoto January 28, 2020 at 12:36 pm
I have 2 of this switch on my office rack. Everything is ok but their cpu temperature makes me uncomfortable, those 2 switches has high cpu temperature (around 70-74 celcius)Ed Luck February 3, 2020 at 7:54 pm
I have a CSS326, basically a slightly cut down CRS326. The temperature is also high on mine – 61-66 celcius when ambient temperature is 21 celcius. On a very hot day recently where the room my rack is located in reached 38C the reported temperatures reached 85C on the CSS326.I am curious where Mikrotik is probing the temperature on these units. If it is the CPU then the heatsink is woefully inadequate. The switch PHY chips are all covered by a large aluminium heatsink, so I’m doubting it’s those unless the thermal paste used is really badly applied.
What’s odd is that I have a Mikrotik RB3011 router right next to it which has a much faster CPU (also ARM) and it never gets above 55C even on crazy hot days.
This high idle temperature of 74C cannot be normal IMHO, believe me
I am based on facts and not on assumptions… As i ve told you in an earlier post, one of my CRS326 i have in production has temp about 72C and it is running without a single problem for months…
Also i am based on the answer of @Elans who as well said the temp is fine…
And also i am based on my experience, 70C is nothing…
So, sorry, i can’t believe you…
@mutluit: why do you believe some random posters on internet forums rather than user support of manufacturer of your device?
Common knowledge[/url] about CPU temperatures these days too much bases on stories of PC overclockers. But physics (specially thermodynamics of solid materials) says that overclockers case is quite different than MT’s case.
The spec of this device says “Tested ambient temperature -40°C to 60°C”
I would like to know how hot the CPU temperature becomes at ambient temperatures of 30, 40, 50, 60C.
Has MikroTik’s test lab performed such tests and could post the results, ie. heat curve(s) or table(s) ?
I hardly can believe this CPU will still function at such a 60C ambient temperature.
Just my guesstimate based on some long time experience and of course logic.
Maybe some brave user is willing to perform such a test/benchmark by heating up his device with a hair dryer and measuring with a thermometer or so…
I myself unfortunately can’t afford to fry my one and only 10G device here
You can email them at Technical Support e-mail support@mikrotik.com
and ask them what sort of tests they ve done to the CRS326 …
Why not?
- Mikrotik states it does. I sure hope they know the specs better than me - or you.
- I’ve seen a delta temperature of about 35 - 40C, based upon my two CSS326. So, I’d say the CPU would be about 100C, with the ambient temperature at 60C.
I know NVidia GPUs go as high as 99C - probably above. I have one GTX1050Ti, and its slowdown temperature is 99C.
A lot of Intel Core i(X) have a thermal throttle of 100C.
The PowerPC CPU, used by Mikrotik on its RB1100AHx2, goes up to 125C.
The AMD Ryzen starts throttling at about 95C.
So, for the last time: It is quite feasible that the CRS326 CPU stands the heat of a 60C environment. Mikrotik says so. A look about thermal limits of others CPUs show that 100C isn’t hard to come by - and we can find some that go beyond.
Asking the same question over and over will get you the same answer.
- The device can stand the heat.
- This CPU works happilly at 70C (CPU temperature, not ambient temperature)
- Yes, it is quite hot. Aren’t machines wonderful?
- Why it doesn’t have a FAN connector? Because it doesn’t need one. This isn’t an industrial switch, and 60C ambient temperature is quite impressive.
And that’s it. I really can’t be more clear than this: the temperature is fine. And if You are worried about the useful life of the product: I have two CSS326, running at 61C and one CRS328 running at about 59C. I bought them 24/08/2018, and they are running non stop since them.
[quote=“, post:31, topic:138630”]
I hardly can believe this CPU will still function at such a 60C ambient temperature.
Just my guesstimate based on some long time experience and of course logic.
[/quote]Why not?
- Mikrotik states it does. I sure hope they know the specs better than me - or you.
Therefore I asked what CPU temperature is to expect at 60C room (ambient) temperature. Below you say 100C. But this simply can’t be true, see below…
- I’ve seen a delta temperature of about 35 - 40C, based upon my two CSS326. So, I’d say the CPU would be about 100C, with the ambient temperature at 60C.
Sorry, but I think you don’t know the full facts: it is stated that the operational temperature of this CPU lies in the range of -30 to +85C,
and this is not very far from the normal 21C room temperature which corresponds to 74C CPU temperature of this device. Don’t you agree?
Ok, I’ll contact the technical support directly. I was assuming they are reading such IMO important forum threads.
Why not?
- Mikrotik states it does. I sure hope they know the specs better than me - or you.
Therefore I asked what CPU temperature is to expect at 60C room (ambient) temperature. Below you say 100C. But this simply can’t be true, see below…
- I’ve seen a delta temperature of about 35 - 40C, based upon my two CSS326. So, I’d say the CPU would be about 100C, with the ambient temperature at 60C.
Sorry, but I think you don’t know the full facts: it is stated that the operational temperature of this CPU lies in the range of -30 to +85C,
and this is not very far from the normal 21C room temperature which corresponds to 74C CPU temperature of this device. Don’t you agree?
[/quote]
I really don’t care about the CPU temperature at 60C ambient. Mikrotik sated it is within operational parameters. So, stands to reason that it is ok. If Mikrotik said it was 110C, what would it matter? The PowerPC of the RB1100AHx2 goes up to 125C!
WHERE it is stated? By Whom? I couldn’t find any spec sheet about this SOC in particular. If someone said “My ARMv7 mobile goes up to 85C”, it doesn’t matter. Because the max temperature varies from CPU to CPU.
So. Unless You find hard data somewhere stating the tjunction spec for this SOC, it doesn’t count. I got data from several CPUs (and one GPU), not because they are directly related to this SOC - but just to show You that a die temp limit of about 100C is far from uncommon.
Do I know the tjunction limit for this SOC? No.
Do You know? Also no - otherwise You would have something better than “I feel it is too hot…”
It is as simple as this: Mikrotik states that THIS SOC can work with ambient temperatures up to 60C. Neither I, nor You, know at what temperatures the CPU would be in this environment.
The difference is: I believe Mikrotik did its homework, and tested the unit thoroughly ate 60C ambient. My trust is backed by the thousands of units on the field, working day in and day out in terrible conditions.
Go read the foruns. You will find bugs, glitches in software, batches with bad hardware. But ONE thing You will not find: someone saying that the hardware couldn’t withstand the temperatures deemed safe by Mikrotik.
Ok, I’ll contact the technical support directly. I was assuming they are reading such IMO important forum threads.
Let us know of the answer, if you wish…
They do read, you already got an answer from Mikrotik Support on a previous post…
Folks, you won’t believe, but MikroTik (or the company assembling the devices) has just forgotten to put thermal paste between the heatsink and the CPU!
I just put thermal paste on the CPU and now the CPU-temperature is only about 55C from previous 70C to 74C !
Problem solved!
It is easy to do: just remove all screws, incl. those 2 on the big heatsink, then from the rear side try to press together, ie squeeze, both sides of the two of plastic things holding the CPU heat sink (actually it is sufficient to do just one of them; just turn the whole thing to a side…), then put the thermal grease on the CPU… that’s all… Use a magnifier to see the two plastic noses at each of the two plastic screw like things… (they are not screws! you have to press both sides of each together…)…
Update: but, unfortunately after closing the case the CPU-temp has now risen to 63C; the above one was with open case… But this action was still helpful.
but, unfortunately after closing the case the CPU-temp has now risen to 63C
So do you still believe they forgot to put paste on the CPU ?
Yes, the upper side of the CPU was blank, no signs of any paste.
It made a difference of 8C: 63C now, 71C before. True, that’s unfortunately not that much 
, but nevertheless…