I have a Mikrotik CRS328-24P-4S+ switch in an attic that gets fairly warm (board temp up to 35C). I have 2 single mode fiber SFPs in it and one copper 10G.
The switch was fairly quiet until I switched on a pc connected to that 10G copper Ethernet. Then fans were running full speed and I could hear them 2 levels below the attic...
Previously (maybe even on this forum) I was told to try fiber and it should be quieter, and I had two old single mode fiber SFPs (branded Opton).
So as I recently found a way to run fiber I did.
Imagine my surprise when the fans started screaming even before I started the PC. All it took was the SM SFP being installed.
I checked the temperature and it was 69C. My other fiber SFPs are 43C.
When I switch the PC on and it connects it drops to about 63-65C but still loud.
The SFPs that are cool are Light Optics LO-SP-10G-LR.
I ordered one more.
I wonder if there can be such a huge difference between supposed 0.8W single mode SFPs there must be also a difference between different 10G copper brands.
So I'm.starting this thread for people to post their verified "cool" SFPs. The only one I know about now is the Light Optics one.
DAC's in general run coolest, for my setup at home i use mikrotik sfp28s (i have a rb5009upr and a crs310 that's linked together, the DACs name that im using to link them is XS+DA0001)
DAC's also use the least power and imo are the best direct links unless you're going inter cabinet/rack/building.
Hard to know your setup but do not run SM/LR sfp at short distance. Also do not mix multimode fiber with single mode sfp. I'm not saying it'll not work but not ideal. Also some copper 10g modules create more heat so if you can stay away from them.
DAC's can be good but sometimes they need coding for vendor locked devices.
presuming hes on a mikrotik forum, that hes using mikrotik equipment, and as far as i know (might be wrong of course), mikrotik stuff never had vendor lock-in like cisco/juniper/extreme networks/dell/nvidia.
Not your specific switch, but I would expect SFP temps to be similar in any gear. To that end, I have 10G optic SFP+ modules in my RB5009, CRS305, CSS610 and two CSS318 switches (all fanless), with a mix of 10GTek, Finisar, Avago, and tested one other I don't recall (In a server now, iirc), and I am seeing temps from 42 to 46C, but no clear winner by brand. Note, though, that these are multimode/SR 850nm with OM4 fiber.
I do use DACs wherever possible, but this is attic down to a room through a wall socket so I decided to run fiber.
My setup is a homelab spread over 3 buildings. Mostly Mikrotik equipment. I have only single mode fiber between building (shortest run is 14m or so if I remember correctly. It has been running for almost a year at that distance (10km SFPs with no problems. I started using crappy gel splices so I needed every dB of power I could get, but I've replaced these connections with properly welded ones long ago.
I never heard about there being a problem running SM at short distance with 10km modules. That is the reason why I chose to not even consider multimode. I'm thinking of maybe replacing my cctv runs with fiber if my PoE switches get destroyed by storm again (it happened once in 5+ years so maybe it's not going to happen - I have cheap "sacrificial" poe switches just for that).
If need be, I could add attenuation, but I'm not convinced it is required, but I'm open to having my mind changed
This run from the attic to the pc would be the shortest of them all if I didn't already have 30m armoured cable with plugs on both ends, so it is 30m despite the real distance being 3m down
I have a mix of 1gig Ethernet over cat 5e in the main building walls (I wish I put microconduits when I was building it 15 years ago), 2.5gig Ethernet for some mini pc based mini cluster. 2*10Gig DAC for 2 PC servers, 2x10gig SM fiber to the main building (the house) and i have fiber run to the third building, but currently dark, it's connected via 1gig Ethernet.
So the system is fairly simple. No 25gig or faster (sadly - waiting for prices to come down).
I'm very much interested in low power/low noise and the difference between these two SFPs, both 10km SM of 20C sitting in the same switch in bays next to each other is what prompted me to start this thread. To get more types that run cool.
basically, i have a test rack where i tested for myself (single mode setup [10km singlemode mikrotik 10gigabit transcievers with os2 singlemode fiber], multimode [mostly cheap om4 multimode fiber optics from amazon and 10gigabit transcievers from 10gtek] and Active optical setup [5m active optical cable]).
All those runs are 10m except the Active optical cable.
The temperature difference was such "not an issue" when running any of those, the fiber optics gonna run hotter because u have chips and encoding + decoding in the transcievers and u have to power the lasers/diodes somehow but they at most use like 1 to 3W of power per transciever, so thats some negligible temperature difference mybe 1-2C+-.
Speaking of running cables, Me personally i don't get why people stress about running multimode anywhere since singlemode is so cheap (i guess it used to be very expensive before so it just remained as a go-to statement when people ask), but the only expensive part about running SMF everywhere is transcievers in my case (because i decided i wanted to go with OEM mikrotik XS+31LC10D).
I bought Mikrotik's official 10gig transciever and a OS2A fiber optics LCLC patch cable from fs.com the whole run is like maximum 3 meters (the cable is 5m long) and i have huge slack everywhere in conduits. The uploaded pictures below is basically my temperature on SFP's (CRS310 -> health -> sfp-temperature)
Im running both as i said a DAC and a Single mode 10gigabit transciever.
All in all, my recommendation is going full SMF. Even tho you don't need the capabilities you get from it, especially in the short runs. Unless youre looking to save money or don't care to min-max the speeds and futureproof-ness of your setup.
It really shouldnt worry you that much tho its all normal temperatures and the only modules/transcievers that really do run hot and really do need adequate cooling is SFP->RJ45 modules. Those are to worry about, other than that you're good with almost whatever.
So it seems we have Mikrotik XS+31LC10D as a second cool running SM SFP in this thread
I've tested Mikrotik's copper 10G SFPs S+RJ10 and sadly no joy. It was also running hot. So if anyone had a cool running copper 10G (if it was possible to let's say limit if to 5m) that would be very useful to me.
My "good" SFPs run at close to the same temperature which makes fans inaudible.
Yesterday night I had to disable the interface, because the noise got rather annoying (there is 20cm of rock wool insulation between the attic and the rest of the house, fans were running at 9500rpm and Sfp temp was 69C.
Today I decided to steal a "good" SFPs from a dual SFP link to the other building and the switch finally runs quiet at a cost of a diminished redundancy. Another sfp is on order so it will not be for long.
I personally wouldn't use an SFP to RJ45 module ever it would be the nuclear and only a last resort for me.
Yes they are that bad. Horrible, they end up cooking themselves and some switches because they need a lot of power to run in the first places, consequently they don't run as long as fiber/DACs/AOC's, in the company we have a much much much bigger failiure rate of RJ45 SFP modules than anything else, speaking of i don't remmember when one of our DAC's failed.
TLDR; Avoid sfp rj45 modules absolutely everywhere, in a huge circumference in possible, it should be your absolute last resort.
Yes, I would prefer anything else, but the problem is better (consumer) PC motherboards usually implement 10G copper onboard. So if you don't want to loose a pcie or USB4 slot you have to use copper.
At the same time it's usually one or two such devices at a given location so buying a switch with a whole block of copper 10G ports makes no sense.
Sadly in today's climate the lifetime of a typical PC is much extended so expandability (USB4, pcie) is very useful. Too useful to "waste" it on network unless one wants faster than 10G.
