Hi,
I have a 5009 with eth1 used at 2,5Gbps as WAN (FO) and I bought some S-RJ10 to connect it to a LASN Switch 24 10G ports.
The issue is quite common (as I understood later): the transceiver goes so hot !
Is there a solution (no, I cannot add fan or extra heatsink)?
I saw other compatible transceiver: Opton, 6COM, HiFiber, FS, Ubiquiti ..
How they behave? same issue?
thanks in advance..
What temperature is it?
A quick google shows a range of SFP+ devices with a maximum of 85°
I have three 4 devices all with Cisco 10Gb SFP+ modules
CRS310-8G+2S+ : 38°
CRS328-24P-4S+ : 46°, 43° and 44°
RB5009UG+S+ : 43°
CRS326-24G-2S+ : 44°
Chances are yours is fine!
Common issue with that SFP+ device. Mine go to 95C between CSS610 and RB5009.
I recently moved and was able to put both devices together in the same technical cabinet and now I use a DAC-connection between both.
I’ll see what I can do in future with those RJ-10s…
The problem is also that in my case, both RB5009 and CSS610 are passively cooled, so no way to cool those transceivers from inside.
Only solution if you still want to use those transceivers is either mount small heatsinks on them and/or use fan (internal or external).
10GBase-T SFP+ modules need active cooling. It’s made for datacenters primarly, not home usage.
10G-Base-SX/MMF is often a better choice (and cheaper) if possible.
Added problem with those specific transceivers from Mikrotik is that there is NO WAY to downgrade speed on the device itself.
If you connect it to a 2.5Gb port, it will comply. But you can not select the speed yourself.
Put 2 on each end and they will always go to 10Gbps, resulting in quite some heat dissipation.
On the 5009 (mounted in a rack, not for home) it started from 48° just few seconds after I inserted, not connected.. and I removed it when I saw it was over 90° a few minutes after I connected it to the 10G lan switch..
The second transceiver was faulty and the third had the same behavior..
From the product page of the S+RJ10:
Any MikroTik device with active cooling that has SFP+ ports can now be used without installing any optical fiber, just plug the S+RJ10 and your network can be upgraded to 10 Gbps, making it ready for the next generation of RJ45 hardware.
S+RJ10 module is supported also on devices with passive cooling, but may require an extra cooling.
I.e. you can only use it with a product that has active cooling, and the RB5009 does not.
You can.
It works.
But it gets freaking hot 
I experimented a while with a SFP ADSL/VDSL modem, and it had the same problem.
The SFP standard has been designed with active cooling devices in mind (datacenter switches) where there is some over-pressure in the cabinet that flows out via the SFP slot. Without that, all except the most modern optical plugins get hot.
https://www.amazon.com/Wiitek-Transceiver-Compatible-SFP-10G-T-S-Supermicro/dp/B07P39G4XJ/
Less than 2.5W Power Consumption
from reviews
I bought three different SFP+ modules for testing.
My use case for this is to connect my Dream Machine Pro to the uncommon 5Gbps gateway port provided by AT&T fiber. The 10GTek doesn’t have autonegotiating so it didn’t work.
The Mikrotik worked. However it was running a bit too hot (85C-ish) and it’s close to being dangerous touching. I bought a SFP+ cage to SFP+ cable and the Mikrotik didn’t work in the extension cable. That made cooling it outside of the UDM Pro infeasible.
Until I discovered this module. Autonegotiation works. Running much cooler at 58C (it is copper gear so this more than just meets the expectations). And it works in the extension cage as well. And guess what? Cheaper than the Mikrotik too.
I have S-RJ01 (NOT S-RJ10) in my 5009 (not poe-model). For some reason i can’t find info about it’s temperature. Where should i look? It is not in interfaces > sfp-sfpplus1 > SFP. There is only setting for shutdown temperature.
S-RJ01 ( 1Gbit ) module doesn’t have status reporting capability. But it consumes minimal power and doesn’t get even warm.
S+RJ10 ( 10Gbit ) module would get hot in normal operation as it’s stated to have up to 2.4W power consumption: https://i.mt.lv/cdn/product_files/sfp_splusrj10_190212.pdf Elevated temperature reading suggests it’s not ambient measurement but transceiver silicon itself. It should handle up to 100C or so.
I put the S+RJ10 in my RB5009 not really understanding just how hot this gets. Unfortunately it is not rack mounted so was just passively cool which was fine before the S+RJ10 was added. I’ve since had to add an external 120mm VAC powered fan that sits behind the RB5009. S+RJ10 temperature dropped from 85C to 75C. Besides throwing high temperature alarm for the S+RJ10 the whole unit especially, the underside of the RB5009 was scorching hot. Now with the external fan the RB5009 is only running warm to the touch CPU reading 35C.
Even a small fan running at reduced speed will help a lot. It is just that slight breeze that you need to replace the air nearest to the unit.
At room temperature an RB5009 sitting on a surface will get 55-60C and that is quite acceptable. With yours getting 85C I presume you are in a hot climate and have no air circulation at all near the router, in that case some fan cooling is indeed a good idea.
Hi,
If you only need 2.5gb, then you can get a 2.5gbe sfp/rj45 device, which runs at a reasonable temperature.
One option: https://vi.aliexpress.com/item/1005005392025773.html
Note: This needs to be run at 2.5g base X which is available for the RB5009, not so much currently on RB4011 which I have 
I can confirm the lower temperature of this SFP+ module. It is used in CRS309-1G-8S+ and replaces an S-RJ10 SFP+ module. I used the S-RJ10 for a connection to a Synology NAS. When data is transmitted temperature increases to 99°C which lead to a shut down of the SFP+ module. With FiberMall 80m RJ45 10G SFP+ module the temperature settles at 59°C even with traffic load.
BR, Michael
These modules are advertised as SFP modules, not SFP+ modules. Do they really run OK when inserted in any SFP slot ?
Has anyone tested them in a CRS324 or CRS112 device ?
Of course not. SFP is 1Gbit.
But after some time when a + standard has become “defacto standard”, people start omitting the +.
My S+RJ10 in my RB5009 has always been running about 65°C - 70°C since day 1