FS SFP-10GSR-85 and SFP28-25GSR-85 Mini Review

FS S5860 20SQ 10G And 25G SFP
FS S5860 20SQ 10G And 25G SFP

We have been using FS.com modules for about two months now and wanted to do a mini-review. You may have previously seen my FS S5860-20SQ Switch Review which was a unique switch combining 10GbE, 25GbE, and 40GbE into a single lower-cost switch platform. As part of that review, we started using FS.com optics and DACs that the company sent for us to try and wanted to share the experience thus far.

FS SFP-10GSR-85 and SFP28-25GSR-85 Overview

The first set of modules we have been using is the FS SFP-10GSR-85. These are the short-range modules that utilize a 850nm wavelength and have a LC connector on one end and a SFP+ connector on the other.

FS S5860 20SQ 10G SFP 2
FS SFP-10GSR-85 in S5860-20SQ Switch

Here are the key specs and the 0.6W or a bit under is very reasonable from our testing.

FS SFP 10GSR 85 Specs
FS SFP 10GSR 85 Specs

The second module we are using is the FS SFP28-25GSR-85. This is effectively the 25Gbps variant of the SFP-10GSR-85 above.

FS S5860 20SQ 25G SFP28
FS SFP28-25GSR-85 in S5860-20SQ Switch

Here the power is certainly up around 50% in our testing, but getting 2.5x the speed for a 50% increase in power consumption seems to make sense.

FS SFP28 25GSR 85 Specs
FS SFP28 25GSR 85 Specs

We have been using these for two months and they have remained stable. We have also tried them in a few other the lab switches for 2-3 weeks each and saw the same behavior. This is what one would likely expect, and we know many of our readers use these modules.

FS S5860 20SQ 10G And 25G SFP
FS SFP-10GSR-85 and SFP28-25GSR-8 in S5860-20SQ Switch

FS.com’s model is to provide low-cost optics while also offering coding options for specific switches. For example, if one wants the modules coded for Cisco, Juniper, Arista, HPE, Dell, or others, that can be specified on the ordering page. FS guarantees that its modules will work when ordered/ coded properly.

FS SFP 10GSR 85 Coding Options
FS SFP 10GSR 85 Coding Options

In terms of cost, the 10Gbps module is $20 new while the 25Gbps module is $39 new which is generally less expensive than modules from the vendors.

FS S5860 20SQ FS DACs And Optics 1
FS S5860 20SQ FS DACs And Optics 1

We also used FS.com’s optical cables and had two of the company’s DACs, both 10G and 25G, that have been working similarly well.

Final Words

Especially at the 10Gbps and 25Gbps end of the spectrum, the technology is mature enough that there is less differentiation between modules. As such, we know a lot of our readers prefer to use 3rd party optical modules such as these FS.com modules. In our experience thus far, they have worked as expected which is about all we can hope for. We also know many of our readers have corporate IT policies where they must use certified modules in switches. While the modules may not void your warranty, if there is an issue with the switch, large vendors are quick to point to a 3rd party module whether that is the culprit or not.

At this time, there are certainly two ends of the market. One end must use vendor-certified modules. The other is building a self-supporting infrastructure where that is not a consideration. If you can use 3rd party modules, then there is an opportunity to greatly reduce the costs of switches. In our FS S5860-20SQ switch review, the optical modules were 40-50% of the cost of the switch, and in other switches that can be much higher. As a result, saving money on optics can have a major impact on costs.

Overall, we have been happy with the optics from FS over the past two months. This is not a large sample size, but they have worked well thus far.


  1. Please do more FS reviews. Bare-metal switches would be awesome. FS has impressive selection of hardware but you can’t find any reviews on them. At least those you can trust.

  2. I would like to see Bit Error Rate comparisons and values in extreme conditions (long cables)

    My clients always ask if there are real differences to the ones which switch vendors supply, other than support.

  3. We basically switched to FlexOptix SFPs as we can even switch coding on the fly and only need one SKU in stock for different switches

  4. Been using a couple of their optics for some time now. Work great.
    One is for my fiber connection straight into my OPNsense box.

  5. We have several hundred 25G SR transceivers from fs.com. It’s good to have a few spare but they are fairly reliable so far.

    That said we did have quite some failures with 100G SFP28 transceivers (single mode). Although reliability might have improved over the years. I have the impression they make changes fairly often. So hard to tell about what they ship now. The technology is less new now and more high volume in any case.

  6. @Tommy:
    I have just bought one of these switches and just received my SFP+ to Base-T converters (also from FS). I tried with a 2.5GbE USB adapter and to my great suprise I got a network connection. and the USB network device reported 2500mbit/s connection (on the side of the Switch it’s reported as 10GBit/s).

    However I wasn’t able to get more than 22MiB/s transfer rate, may be an issue with my test setup or may be a problem with the device.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.