SFP/SFP+ NIC question

Good day, do any one here have any tips, or maybe someone has experience using SFP/SFP+ network cards for x86 router to PC? I know exactly how to get an RJ45 card, just choose intel 82xxx and it will always be 100% working. What about optics? Can I take HP, Emulex, Broadband, Broadcom... etc? How do I understand the compatibility of the chip and card with OpenWrt?

Second question: what's matter more, the card and card controller or SFP/SFP+ module? For smooth working inside OpenWrt?

Thanks for any opinions.

Check out this other thread also

After seeing the above post i got a couple of Connect-X3 card's which accept various brands of transceiver and DAC cables

Check out the manufacturer of the card and switch to see compatible parts

I used Cisco and Ubiquity DAC cables

Ubiquity and ONTi fiber transceivers

I use


Using my x86 router also as a switch, have MOBO with x4 i210 rf45's and also 2 x2 intel nic's. Switch generatrs latency's wich i won't see.

My x86 build i have a dual port 40 Gbe card which have a QSA adapter to convert to 10 Gbe which i will use with OpenWRT, im waiting for the other adapter

40GB - insane speeds.. started reading about Connect-X3 you write, is Connect-X3 = mellanox?

Yes however they have a range of cards Connect-X 2,3,4 and 5

Hi folks.

I have used a collection of SFP+ 10/40GB cards in OpenWRT now. I can summarise my limited experience as follows:

Mellanox Connect-X 3

  • Available in single and dual port PCIE or OCP form factor (OCP requires adaptor).
  • Very low cost on pre-owned market (~$15 for OCP, $40 for PCIE)
  • Very low power requirements (3.4W on single port version)
  • Accept a wide variety of SFP modules (tested with Netgear, Intel, Edgeware, Cisco)
  • Drivers in Master but not released - so requires custom build.

Intel X520-DA2

  • Drivers already in release builds
  • Reasonably cheap pre-owned ~$60
  • Some versions require a driver flag to be switched in order to work with non-Intel SFP modules.
  • Higher power consumption (10W)

Intel X710

  • 40Gbps capable
  • Lower power consumption than X520
  • Some versions are locked to Intel-only SFP modules.
  • Drivers in master but not release builds.

All in all, I would recommend the Mellanox card on the grounds of power consumption and price if you are comfortable compiling or using the nightly builds. For those on release builds, go for Intel X520.

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Thanks for such a great answer!
Do x520's need some kind active cooling?

Cooling of SFP+ cards is a difficult equation becuase the power-draw of the SFP modules also affects the heat. Generally speaking, if using optical (10GBASE-SR or 10GBASE-LR) modules or Direct Attach Copper (DAC) cables then you'll be fine with passive cooling.

The biggest impact is if using 10GBASE-T (10Gb Ethernet over Cat6/Cat7 copper cable) as these modules can draw up to 30W each!! In my passively cooled system these ports reached temperatures of 98 degrees celcius. There didn't seem to be any negative impact from this, but it made me uneasy so upgraded everything to optical. Now the ports run at around 55 degrees celcius with passive cooling.

Those 2 Mikrotik switches i posted above is also passively cooled and thus quiet (no fans)

The CPU is same but clocked higher in the 24 port switch i believe

Seen CPU upto 65 degrees in 24 port

MikroTik Routers and Wireless - Products: CSS326-24G-2S+RM

MikroTik Routers and Wireless - Products: CRS305-1G-4S+IN

I am also not using Ethernet transceivers

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