10Gb/s Ethernet: switching to a Broadcom SFP+ module :: Giles' blog
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10Gb/s Ethernet: switching to a Broadcom SFP+ module
Posted on 16 June 2026
in
TIL,
Gadgets
Back in April, I upgraded my home LAN to 10Gb/s.<br>The in-wall cabling is CAT-6 or similar, so I had to use 10GBASE-T. Now, the router<br>I'm using, and the switch in my study, provide 10Gb/s through SFP+ cages; that meant<br>that they needed 10GBASE-T SFP+ modules in order to connect.
That kind of module is known to run hot -- sometimes too hot to actually work. The<br>modules in reggie, the router, appeared to be running OK (see the linked post above<br>for charts), but the one in nigel, the study switch, was a worrying 93C. I tried<br>sticking some mini-heatsinks on it, which<br>seemed to help a bit. But the weather got warmer, and eventually the module overheated.<br>I lost access to the Internet from the study, and checking the metrics showed me this:
You can see that it's "flapping": the temperature gets up to a level where the module<br>shuts itself down for its own protection -- about 95C, I think -- and then when it<br>has recovered, it switches on again, the temperature rises, and the process repeats.
I was able to work around the problem by switching on the air conditioning in the study.<br>But normally I only have it on when I'm in there, and keeping aircon on 24/7 just to keep<br>the network working felt like the wrong solution.
It was time to switch to a more power-efficient SFP+ module.
My original 10Gb/s post had quite a lot of discussion on Hacker News,<br>and xxpor mentioned that there are two generations of 10GBASE-T SFP+ modules:<br>old ones using a Marvell chip, and newer ones using<br>one from Broadcom. blunden on the ServeTheHome forums<br>made the same point. The Marvell-based ones were known to run hot, and they both recommended<br>finding Broadcom-based ones.
I'd confirmed that the MikroTik S+RJ10 that<br>I had in nigel was indeed a Marvell one, so the solution was pretty simple: get a better one.<br>So I went on Amazon and picked up a 10Gtek ASF-10G-T80-INT.<br>Checking...