Realtek unveiled low-cost, low-power 10GbE RTL8127 (PCIe) and RTL8159 (USB 3.0) controllers at Computex 2025. Since then, we noted that RTL8127-based M.2 and PCIe 10GbE cards had already launched for as low as $35.
However, a new X post by Jeff Geerling reminded me it was time to check on those RTL8159 10GbE to USB 3.2 adapters. So let’s do that now, starting with the Wisdpi WP-UT9 mentioned in the post/tweet.
Wisdpi WP-UT9
WisdPi WP-UT9 specifications:
- Chipset – Realtek RTL8159
- Ethernet – Up to 10GbE RJ45 port; backward compatible with 5 Gpbs, 2.5 Gbps, 1Gbps, and 10/100Mbps Ethernet
- USB – USB 3.2 Gen2 Type-C port; backward compatible, but slower ports will impact performance; USB hubs/docks and long cables are not recommended either
- Misc – 2x LEDs – Amber (Link) / Green (Activity)
- Power Supply – Via USB-C port
- Dimensions – 59 x 29 x 13 mm
- Weight – 58.8 grams
The adapter may work out of the box on some systems without additional drivers, but in case you do need them, Windows, Linux, macOS, and UEFI drivers can be found on the Realtek website.
The WP-UT9 can be purchased for $79 on the WisdPi website before shipping, or about $87 shipped to the US (tariffs may also have to be applied).
XikeStor SKN-U310GT
For the next model, I went to AliExpress and found the XikeStor SKN-U310GT there. It is one of the most popular RTL8159 adapters, having sold close to 200 units. The price I’m shown is $57.05 (welcome deal) with free shipping, but it regularly goes for $69.70.
The XikeStor adapter has a similar design to the WisdPi one with an RJ45 port, a USB-C port, and an aluminum alloy enclosure. However, it’s quite larger than the WT-UT9 at 99.2 x 42 x 22 mm.
Since it’s one of the most popular items, we also have some user reviews. Several people mentioned the adapter does not get hot, and one person tested it with iperf3, reporting 7.37 Gbps and 6.5 Gbps DL/UL transfer rates. It’s a bit lower than the 9.4 Gbps I would have expected, but it looks typical for a 10 Gbps port as we’ll discuss further below.
The SKU-U310GT is also listed for $89.99 on Amazon, and we have more iperf3 test results there:
- GMKtec EVO-X2 (Linux 6.18 preempt-rt + Realtek driver v2.21.4): 8.06 Gbps
- ThinkPad X1 Extreme Gen 2 (Linux 6.14 + Realtek driver v2.21.4): 8.62 Gbps
- ThinkPad X1 Extreme Gen 2 (Windows 11 + Realtek driver dated 10/9/2025): 6.13 Gbps
- MacBook Air M4 (macOS 26.2): 6.35 Gbps
Results in Windows and macOS look lower, but the iperf3 version in Windows was not mentioned, and it may matter here. Surface temperature was measured at just 33°C after an iperf3 test.
The cheapest option – Lekuo DR59R11
The cheapest model I could find on AliExpress was the Lekuo DR59R11, selling for $44.81, but marked as an “early bird” offer with a single unit at that price. If I do a search for RTL8159 on AliExpress, I’m shown several options at around $55 on mobile, but somehow the prices increase if I perform the same search on desktop…
It’s basically the same design as the others with RJ45 and USB Type-C connectors. The dimensions are 84.40 x 48 x 29 mm. But what I found interesting, besides the low price, is that they shared some performance data based on the USB or Thunderbolt port used.
If you want to extract the full performance out of a Realtek RTL8159 adapter, you’ll need a system with a USB 3.2 Gen 2×2 20 Gbps port. Good luck with that, since computers and laptops with a 20 Gbps port are pretty rare, and I don’t believe I’ve ever reviewed one myself. More importantly, those 40 Gbps Thunderbolt and USB4 ports you’d think would perform great, actually operate in compatibility mode, and the company tested just 7.11 – 7.44 Gbps and USB4 port, 5.97-6.01 Gbps on a Thunderbolt 4, and only 3.54-3.92 Gbps on a Thunderbolt 3 port, or about the same as on a USB 3.0 5 Gbps port.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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These look much better than the ones that were shown at Computex 2025. Shouldn’t be any thermal issues either, unlike the green model that was on display at the Realtek booth, which even the Realtek guys were concerned about.
One thing to keep in mind is that these won’t work at full speed with a Mac, since Apple doesn’t support 20 Gbps USB 3.2 Gen 2×2 speeds.
Also note that those USB4 numbers only applies to AMD/ASMedia implementations of USB4 for now, possibly also Qualcomm, since Inte has gone down the same router as Apple when it comes to Thunderbolt and don’t support USB 3.2 Gen 2×2 and as sometimes these ports are labelled USB4… That said, Intel hardware might have separate USB 3.2 Gen 2×2 ports where it would work. That compatibility mode nonsens isn’t the issue, it’s simply a hardware limitation that that company clearly wasn’t aware of.
USB 3.2 Gen 2×2 isn’t rare as such, but not all chipsets support it and it uses up two “lanes” of USB 3.2 Gen 2 from the CPU/chipset, which is why some board/device makers chose not to add support for it as well. For whatever reason, the onboard connector for the case USB-C port is often the 20 Gbps port.
It would be really useful to have power consumption numbers for these.
Since the adapter has a bug heat sink, I assume it consumes several watts at least.
It’s a sub 2 W TDP for the PCIe parts with PHY (varies a bit by SKU) and just above 1 W for the parts without PHY, but Realtek didn’t provide any power figures for the RTL8159 at Computex. The standalone PHY is 1.65 W. I would hazard a guess and say that the power draw tops out somewhere around 2.5-3 W with the USB bits included.
This is awesome! Price on 10GbE network switches are also finally getting lower too!
Jumbo frame support????
Yes.
Simply testing iperf3 on these isn’t enough. Their 5gbe USB devices are highly unreliable under linux using their drivers and there’s no in-tree kernel support. NFS instantly breaks them, and even when I moved to samba from NFS they would break after a few hours. There’s discussion of this on the sth forums. It’s been a known issue for a year now with no fixes.
Did anyone with issues try contacting the company they bought their adapter from, asking them for support?