10gig SFP+ and Win 11 - ConnectX 2 replacement

Hi - TLDR; I am building a new PC due to some hardware failures, and I will be going Win 11 vs 10 which I currently have. I run a ConnectX 2 on my desktop and one in truenas to get a 10 gig link - this has been working great. Problem is, I figured I would confirm the X2 would work in Win 11, and looks like it will not…

What would be the best option to go to get this functionality back? I am considering a ConnectX 4 in my PC, or potentially a Intel x710-da2. Ideally, I want this to be as cheap as possible which is why I would only want to replace the 1 on the desktop (leave the X2 in truenas), and hopefully reuse the Finisar FTLX8571D3BCL SFP+ transceivers I already have.

Any recommendations either way? Also, just to make sure I understand things correctly, I should be able to use a SFP+ in a SFP28 port, and barring that working, a SFP28 transceiver would be able to talk to a SFP+ in a direct connection, correct? I am a bit of a novice with SFP/anything besides gigabit rj45…

Thanks for any advice or recommendations.

SFP, SFP+ and SFP28 should be electrically compatible. No idea if any manufacturer felt “special” here.
When you put a piece of fiber between them, then the transceivers will do as their ports specifies (might have to disable auto-negotiation or limit the speeds offered).

Intel E810-XXVDA2 can be had for 350€ in the EU (brand new that is!).

Good to know, thanks for the info!

As far as price, I’m looking at used cards for ~40-60 USD.

For what it’s worth, I picked up a Intel x520-da2 with a transceiver for 22 bucks on eBay. Looks like it’s supported in the Intel driver package.

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ConnectX 3? You can get these on ebay cheap. Haven’t confirmed that it runs on win11 but I’m about to in a new machine I just built. I should be able to just install the win10 driver. The x520-da2 is pcie 2 and needs 8 pcie lanes. The connect x3 is pcie3. A single port card only needs 4x lanes and is pcie 3.0. So you can put this in the lowest slot and not have to steal lanes from your gpu slot.

I have recently bought multiple
cx3 at $15
cx3pro at $30
cx4lx at $40