FS S5850-48S6Q 48x 10GbE and 6x 40GbE Switch Review


Pluggable Modules and Performance

A major theme of this switch is cost savings. The cost of the switch is only one part of the total cost of a switch solution. The other, and the potentially bigger one is the optics and pluggable modules.

FS 5850 48S6Q With QSFP SR4 40G And MTP Pro Cable Installed
FS S5850 48S6Q With QSFP SR4 40G And MTP Pro Cable Installed

We had the FS QSFP-SR4 optics that use MTP-12 cables to transmit 40GbE speeds from the QSFP+ ports. These modules are only $39 at the time of this writing for the vendor-supplied modules.


We also have 10G SFP+ 10km modules to test with. These single-mode fiber modules are only around $27 at the time of this review.

FS 5850 48S6Q With SFP 10GLR 31 Installed
FS S5850 48S6Q With SFP 10GLR 31 Installed

Finally, we have the FS SFP-10G-T modules that allow one to use 30m 10Gbase-T runs with this switch. That expands the use cases for a switch like this. These modules are currently $65.

FS 5850 48S6Q With SFP 10G T Installed
FS S5850 48S6Q With SFP 10G T Installed

In terms of performance, we were passing traffic through the switch and these optics and the SFP+ to 10Gbase-T at line rate. That is what one would expect. We also had FS cables and we tested the MTP/MPO cables on the Fluke MultiFiber Pro and the Versiv 2 (a mini-review for that coming soon.)

We will quickly note that the FS S5860-48SC we reviewed has a lot more bandwidth with eight 100GbE SFP28 ports instead of the six 40GbE ports here. It may not seem like a large difference just looking at the switch, but it has around 77% more potential throughput because it uses the higher-speed SFP28 ports.

The bottom line is that saving even $50-100 per pluggable module is several thousand dollars across the switch’s 54 ports. That is a big part of FS’s value proposition since they are targeting being a cost-leader in the space.

Power Consumption

Power consumption varies a lot depending on the modules used. On 208V power, we saw idle was around 80W with just the management ports and a single SFP+ module plugged in. FS lists typical power at 150W and maximum at 190W.

FS 5850 48S6Q Switch 400W 80Plus Gold PSUs
FS S5850 48S6Q Switch 400W 80Plus Gold PSUs

The 400W power supplies we are very happy actually have that 80Plus Gold rating, but they could have been lower power to drive this switch even in 1+1 redundant mode. For those wondering, we were well above 35dba in our testing and could get above 40dba without even fully filling switch ports or loading the switch so we are going to say from a noise perspective this should be kept in an equipment closet or data center.

Final Words

This is one of those really interesting products. For many of our readers, we think it is time to transition to 25GbE. If you saw our Welcome to the Intel Ice Lake D Era with the Xeon D-2700 and D-1700 series piece, the new Ice Lake-D chip is going to drive firewalls and edge devices to 25GbE. The 25GbE transition is now well underway in the server space where we are no longer seeing many servers we review with SFP+ and see SFP28 instead. As such, we need to get into the cost aspect of this switch.

FS 5850 48S6Q Switch Front Open 2
FS S5850 48S6Q Switch Front Open 2

At $6000-$8000, we think the 10GbE/ 40GbE switch with a lower-power CPU would be a tough sell. At around $3000 with the availability of low-cost optics, and a decently functional web GUI for the SMB market, these become significantly more attractive. FS is pushing cost optimization and is able to offer a relatively low-cost switch in this class as a result.

FS 5850 48S6Q With QSFP SR4 40G And MTP Pro Cable Installed
FS S5850 48S6Q With QSFP SR4 40G And MTP Pro Cable Installed

We think that our readers should look into what features they need versus what this switch has, and then decide whether it is right for their environments at the price point. Buying switches is always an important decision, and the S5850-48S6Q offers quite a bit for the price. Also, let us face it, in many segments switch supply has been tight so there is also an aspect of this which is just simply having a switch that one can purchase and get reasonably quickly in the market we are currently in.


  1. I think FS is really doing themselves a disservice with the fake-looking reviews, that just makes them look super-shady. Also, they should ditch developing their own OS and instead support an open OS like SONiC, lower cost for them and a larger customer base especially at the price point. I have an FS switch and the typos alone don’t inspire a lot of trust in the Web GUI.

  2. Makes me laugh that companies are still including those “warranty is void if seal is broken” stickers. In the US at least it’s not legal and they can’t use it as a grounds to void your warranty.

  3. I’ll agree with Nils SONiC would be best, but then they’d need a better CPU and it’d be more expensive.

    STH is the only site I trust for these reviews of FS products. All the rest seem like they’re fakes. All of the FS.com reviews look like fakes. It’s so shady.

  4. FS does not produce any switches, the switches of FS are OEM, and the operating system is also OEM, and FS is not responsible for development.

  5. Their website claims a forwarding rate of 1071.4 Mpps, however, I have some doubts that the low power (small heatsink!) PowerPC can keep up with anything demanding

  6. FS is the new back door into the U.S

    Due to most of the other vendors being shut down,
    give it a few years & they will be on the banned list as well…


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