Idle -73°
If Cpu Load 3-6% CPU temperature 79-80°. Router box hot.
It`s good?
What was the ambient temperature at the time of these temps?
Approximately 25°C. Normal room temperature. Router surface hot.
Generally speaking I would expect something like:
18-25° for the room
idle 35-45°
low cpu 40-55°
medium (up to 50 % CPU) 60-75°
high CPU usage 80-95°
If the router is hot I assume the heat sink is doing some work at least. Can you messure power usage? Also have you any issues like portflapping. I can see another topic here where this is an issue.
Still hope this is a software issue!
I used it for about 3 days with 7.24rc2 installed, and it reports CPU temp of 70–78C when the ambient temp remains between 26–30C.
At this time, the thermal camera showed a surface temperature of 53C on the side with the Mikrotik logo, 67C on the heatsink, and approximately 64C on the opposite side (without the logo hole).
The be3's CPU temp is definitely higher than that of the ax3 (-63C), which has a faster CPU clock, and I suspect this is because many devices such as the QCN6274, Bluetooth, and USB 3.0 hub have been added.
I am currently using a USB fan installed, and the cpu temperature remains between 50–60C.
*Update: I rebooted my router 5 hours ago, and with an ambient temperature of 28-29C, the CPU temp reached 75-76C in idle state. (No USB fan, powered via PoE)
In this state, the power consumption reported by the PoE switch is 14W. (3 RJ-45 ports in use, no Wi-Fi devices)
from datasheet: Max power consumption without attachments 20 W
i think that borderlines what such a small device can dissipate passively, would be reasonable expect it to be hot
rb4011 wifi version declares 23 w being bigger with a great metal surface to dissipate, and still hot to the touch
having said this i think we must gauge our temperature expectations accordingly
This is too high for my likings. But I wouldn't considered the be3 media either way.
But 79° at idle consuming 14W. That's a lot of powa for nothing.
The 14W idle might be an issue at the end of the month when you pay the electricity bill, but the 70-80° idle is crazy in an absolute way, particularly considering that it happens at 30° ambient temperature.
The device is rated as:
MTBF Approximately 200'000 hours at 25C
Tested ambient temperature -30°C to 50°C
What would be idle temperature @50°? 90-100°? 
Anyone tried oil cooling of a Mikrotik device?
70-80C is indirect result of 14W heat generator without active cooling.
There, I fixed it for you 
:
The whole thing was kind of predictable. People want 2.5GbE. These transceivers consume more power than GbE. Let's assume just +0.5W/port. That 2.5W.
In the ac times you could have a 2.4GHz + 5GHz wifi arrangement with a dissipation of 2-3W total. Wifi 6 doubled this, mostly due to the necessary DSP capacity. Then you add a third radio. (Plus even more DSP.)
At this point you can use active cooling, design your product as a giant heatsink with some electronics attached, or do what some other manufacturers do, whose similar product reportedly routinely die from being placed in a closet/behind a TV, etc.
We probably have to accept that these devices will grow and be full of vents to maintain any sort of tolerable temperatures.
/system/health> print Columns: NAME, VALUE, TYPE # NAME VALUE TYPE 0 cpu-temperature 63 C
Room temperature is 21 degrees c.
The temperature warning is set to 105 degrees, not sure if this is platform specific
/system/health/settings> print
cpu-overtemp-check: no
cpu-overtemp-threshold: 105C
cpu-overtemp-startup-delay: 1m
EDIT:
If I turn the BE3 vertical, its dropped to 55 C after a couple hours.
Had a look at my cAP AX to see what they pull and it is 6.1 W with around 15 connected clients. So 14 is a big step up if it is idle 14 W. Not that the devices are 1:1 but still 14 W idle is more then I expected.
U7 Pro, at my parents house, draws 8.57W right now from the switch.
7 clients on 2.4GHz radio, 3 clients on 5 GHz and 1 client on 6GHz.
But all of you are looking at this in the wrong way... Imagine you have a couple of these to put in production. You are drinking your morning coffee and you like it hot, not luke warm. Well just leave it on be3 and problem solved.
Run iperf3 test a couple of time and you can even boil the water and make some tea.
Jokes aside, 80°C idle temp and 14W idle power consumption is ridiculous.
There are valid reasons for having a larger power draw than the cap ax. I wouldn't really expect 14W, I would guess something like the U7 Pro, so somewhere just under 10W. Maybe the measurement was done on the mains connector side? (Which is obviously more than on the DC side, but more importantly, the cheaper mains meters are notoriously inaccurate, especially for these types of switch mode power supplies.)
Anyway, the 42 degC above ambient is not too bad, considering that 105 is a usual limit for these chips.
I think the higher temperatures are mostly a design choice for the size and venting of the enclosure, not some strict technical limitation of the technology. Also, one must not forget that these chips have packagings that have a high thermal resistance, so at least some of this is Qualcomm's choice. Additionally, these readings have to be taken with a huge grain of salt, as these temperature probes are very inaccurate.
I find 14 W of idle power consumption unacceptable for such a small device. Unless this is a measurement error, the power consumption is simply too high.