The Arrival of CHEAP 10GbE Realtek RTL8127 NIC Review

Cheap 10GbE or 10Gbase-T has arrived with the Realtek RTL8127. Oftentimes, users have had to choose between the Marvell AQC107 and AQC113 families for low-cost 10Gbase-T or several used enterprise NICs from Broadcom and Intel. The data center NICs tend to have more capabilities and offloads, but power consumption is higher, and new pricing can easily be five times higher. Now, with the Realtek RTL8127, we have a 10Gbase-T solution that is already producing under $50 new NICs, which only use a PCIe Gen4 x1 lane and sip power at sub 2W for the chip and sub 3-4W for the board. Cheap 10Gbase-T is now attainable.

Also, please note that we purchased a few of these cards, and the one we sacrificed for photos did not work at the end. This is not sponsored, but if you want to find the cards we purchased and current pricing, you can check out the AliExpress affiliate link 1 and link 2. We thought we would get different cards, but that was incorrect, and we received the same cards, only a few serial numbers off.

Realtek RTL8127 NIC Overview

We ordered a few of these NICs, but they all arrived looking essentially the same. As a quick note, these came with both brackets.

While the front of the NIC has the primary components, the back does not have a lot going on. Something small, but fun, is that instead of a model number, we have simply “RTL8127 PCIe 4.0×1 10Gbps Network Adapter.

The heatsink is also interesting. The fins go top to bottom, not front to back. So the airflow is probably better aligned to a workstation versus a server.

Here is another view of the heatsink.

The PCIe Gen4 x1 is really useful. Some motherboards have x1 slots. Using an older PCIe Gen3 10GbE NIC would require a x2 electrical or, realistically, at least an x4 physical slot. An x1 slot is just very flexible.

We pulled off the heatsink and got to the RTL8127 NIC chip.

It looks like most other single port Realtek NIC chips we have seen.

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Realtek RTL8127 NIC Performance

We took two NICs, hooked them up “back-to-back” and this is what we saw:

This is reasonably good in terms of performance, we are certainly hitting 10GbE speeds. Something worth noting is that we did this using the card versions of the NICs. We also have a number of systems that integrate these NICs, and so we double-checked our results. We tried PCIe card NIC to the onboard NIC, and onboard NIC to onboard NIC. The results looked almost identical to the above, so it seems not to matter how these are implemented, so long as they are on PCIe Gen4 x1 lanes.

Key Lessons Learned

Let us take a step back for a moment. We have had 10Gbase-T NICs for many years at this point. The Realtek NICs tend not to have the most virtualization features. Support for these in Windows and Linux is ok, but you most likely want to go to Realtek’s site and download drivers today. Many OSes will not recognize these NICs out of the box.

The impact of this NIC is really twofold. First, this is the footprint, and an x1 electrical interface that is ideal to integrate into motherboards. Even the PCIe Gen4 x1 card is a bit awkward. Adding an x1 slot consumes significant motherboard space, so we usually do not see them on mITX motherboards. The package is perfect to integrate onto motherboards that previously had PCIe Gen3 x1 lanes driving 2.5GbE NICs. Having a Gen4 x1 NIC means we effectively get four times the bandwidth due to the better lane utilization.

Perhaps the bigger benefit for the PCIe card is the cost. Folks have given us wildly different pricing, but $10ish for a NIC seems to be common to hear at this point. That means these PCIe cards are $35-45 each. Adding 10Gbase-T for $45 if you have an open PCIe Gen4 x1 slot and around 2-3W of power consumption is awesome.

The bigger challenge is that with an x1 NIC, we are now at the end of the line for 10GbE. With a PCIe Gen5 x1 lane we can support 25GbE, so in the future lanes will be massively underutilized with 10GbE NICs.

Final Words

Hopefully we will see more of these NICs, along with some of the fun derivatives in the next few months. This is one where we are probably more excited for the integrated NICs than the PCIe cards. At the same time, at $35-45 for the NICs this makes the NIC side of adding 10Gbase-T networking very affordable. While we do not get the virtualization offloads and so forth, 10GbE networking is really easy for modern processors to handle. That is why we can see low-power Arm-cores drive 10GbE firewall/ gateway appliances without issue.

Still, for many of our STH readers, these Realtek RTL8127 NICs are going to open up awesome systems.

Where to Buy

If you want to find the cards we purchased and current pricing, you can check out AliExpress affiliate link 1 and link 2.