A new $89 USB-C network adapter can push data at 9.5 gigabits per second on a Windows 11 laptop, potentially making 10-gigabit networking as portable as a thumb drive. But as the first real-world tests of the Realtek RTL8159-based XikeStor SKN-U310GT reveal, tapping that speed requires a very specific—and often misunderstood—USB port.

That finding, published in a detailed review by ServeTheHome on April 10, 2025, shows a compact aluminum dongle finally breaking the speed barrier that has long kept wired multi-gigabit Ethernet tied to desktop PCIe slots. For Windows users, it means that fast local backups, NAS transfers, and large media projects can now move at near-10GbE rates without cracking open a PC case—provided your device has proper USB 3.2 Gen 2×2 support.

A 10GbE dongle that actually works—with one critical string attached

The XikeStor SKN-U310GT isn't the first USB Ethernet adapter, but it's among the first to push past the 5Gbps ceiling that previously defined the category. Inside its heat-sinking aluminum shell sits Realtek's RTL8159 chipset, designed explicitly to bridge 10Gbase-T networks and USB.

ServeTheHome's testing confirms that on a Windows 11 x86 machine with a 20Gbps USB 3.2 Gen 2×2 port, the adapter hit a peak throughput of 9.5Gbps. That's close enough to the 10GbE theoretical maximum that most users won't notice the loss. Transfer a 100GB video project, and it finishes in about 85 seconds instead of 13 minutes over gigabit Ethernet.

But drop down to a 10Gbps USB 3.2 Gen 2×1 port—still very common on modern laptops—and speed plummets to roughly 6.6Gbps. On an Apple M4 MacBook Pro, it managed only 6.3Gbps, and on older 5Gbps USB 3.2 Gen 1 ports, throughput capped under 5Gbps. The adapter works everywhere, but it only sings on a true 20Gbps USB-C link.

Why the driver situation matters more than you think

Unlike plug-and-play gigabit USB adapters that Windows 11 recognizes instantly, the Realtek RTL8159 may leave you staring at a non-functional network connection. ServeTheHome found that Windows did not always have a built-in driver ready. Having another working network connection—Wi-Fi, for example—let Windows Update fetch one, but many users will need to download and install the driver from Realtek's or XikeStor's website before the adapter appears in Device Manager.

"We always suggest getting the latest from Realtek's website," the review notes. That's more than just good practice. USB NIC drivers sit in a sensitive path, mediating between power management, USB controller quirks, and networking offloads. A stale or mismatched driver can cause random disconnects, poor throughput after sleep, or even silent data corruption under heavy load.

For IT staff who plan to carry this dongle between machines, the advice is clear: keep a copy of the latest driver on a separate flash drive. Don't assume an enterprise endpoint will allow driver installs on the fly. In small offices and homelabs, pre-loading the driver before the adapter becomes mission-critical avoids frustration.

Decoding USB-C: What your port speed means for network performance

Perhaps the most confusing part of this whole story is USB branding. The SKN-U310GT uses a USB-C connector, but USB-C alone tells you almost nothing about speed. A single USB-C port can carry USB 2.0 data at 480Mbps, USB 3.2 Gen 1 at 5Gbps, Gen 2 at 10Gbps, Gen 2×2 at 20Gbps, or even USB4 and Thunderbolt 4 at 40Gbps. For the RTL8159 adapter, only the 20Gbps mode provides enough overhead to push near-10GbE throughput.

"You really need to check your laptop's specifications," the ServeTheHome review emphasizes. On a desktop, rear motherboard ports often have higher bandwidth than front-panel USB-C connectors. Laptops may have one USB-C port that supports 20Gbps while another only does 10Gbps. A Thunderbolt 4 dock in between may add latency or bandwidth sharing that further reduces performance.

In real-world use, that means buying this adapter without checking your port spec is a gamble. A user with a two-year-old Windows ultrabook that only supports 10Gbps USB-C will still see a speed boost over gigabit Ethernet, but they'll never reach the 9.5Gbps peak. They're effectively paying for a 5GbE-capable device with extra headroom.

Real-world speeds: From 9.5Gbps down to 4.7Gbps

ServeTheHome ran the adapter through multiple USB generations and platforms. The numbers paint a clear ladder:

  • USB 3.2 Gen 2×2 (20Gbps, x86 Windows 11): 9.5Gbps peak
  • USB 3.2 Gen 2 (10Gbps, x86 Windows 11): 6.6Gbps
  • USB 3.2 Gen 2 (10Gbps, Apple M4 MacBook Pro): 6.3Gbps
  • USB 3.2 Gen 1 (5Gbps, x86 Windows 11): 4.7Gbps

Those figures line up with the expected overhead of USB protocol encoding and system architecture. They also expose a nuance that spec sheets hide: even a 10Gbps USB connection cannot fully saturate a 10GbE link. Ethernet frames, USB packetization, and host controller scheduling all eat into usable bandwidth.

Slight variability was also noted—the adapter's throughput varied more than a dedicated PCIe 10GbE card. That's normal for USB devices, which share bus resources and can be affected by CPU load, other USB traffic, and power delivery. For consistent line-rate 10GbE, a PCIe card remains superior. But for bursty file transfers and portable use, the variability often goes unnoticed.

What this means for home users, creators, and IT pros

The SKN-U310GT reshapes who can access 10-gigabit Ethernet, and for what.

For home NAS owners and creators, it's a game changer. A photographer backing up 500GB of RAW files, or a video editor moving 8K footage to a centralized NAS, can now do so at wire speed from a laptop. No need for a bulky desktop or Thunderbolt dock. Tuck the adapter into a laptop bag alongside a Cat6a cable, and you have instant high-speed access anywhere.

For homelab builders, it lowers the barrier to entry. Previously, adding 10GbE to a mini-PC or a machine without a free PCIe slot meant buying a new system. Now, a $89 dongle plus a compatible switch—something like a MikroTik or QNAP offering—puts multi-gig networking within reach of small form-factor setups.

For IT professionals, the adapter becomes a field tool. Rapid workstation imaging, switch-port validation, emergency connectivity when a built-in NIC fails, or even temporary 10GbE drops for large deployments are all suddenly practical. The caveat is driver installation on locked-down corporate machines; admins should pre-stage the driver or have an alternative path to get online.

But the adapter is not a server NIC replacement. It lacks advanced features like SR-IOV, RDMA, and hardware offloads. For sustained high-throughput server workloads or latency-sensitive applications, internal PCIe networking still wins. Think of the SKN-U310GT as the portable wrench in your toolkit—not the permanent plumbing.

Thermals, power, and the coolness factor

Early 10Gbase-T adapters ran notoriously hot, often requiring active cooling. The RTL8159 breaks that trend. ServeTheHome measured power draw between 2.0 and 2.89 watts, depending on the platform. While slightly above Realtek's claimed 1.95W, it's still remarkably low for a device pushing 10-gigabit traffic. By comparison, merely lighting up a 10Gbase-T switch port often consumes 1.6–1.8W.

"The Realtek RTL8159 is actually doing a phenomenal job" on power, the review states. The aluminum enclosure acts as a passive heatsink, and during testing, there was no sign of thermal throttling. That means the adapter can sit in a warm equipment closet or behind a laptop without becoming a fire hazard.

For mobile users, low power matters. A 2.5W dongle won't drastically drain a laptop battery during a few large file transfers, and it avoids the "USB device drawing too much power" warnings that plague some power-hungry accessories. Just avoid burying it under papers or behind a hot docking station—give it some airflow.

Before you buy: A compatibility checklist

If you're eyeing the XikeStor SKN-U310GT or any other RTL8159-based adapter, run through these steps first:

  1. Check your laptop or desktop's USB-C spec. Look for "USB 3.2 Gen 2×2" or "20Gbps" in the manual. If it only says "USB 3.2" or "USB-C 10Gbps," expect mid-6Gbps speeds.
  2. Keep in mind that USB4 and Thunderbolt 4 ports may not expose 20Gbps USB 3.2 Gen 2×2 for this adapter. ServeTheHome's Mac testing suggests that Apple's implementation doesn't support the mode, though Windows machines with USB4 may behave differently.
  3. Have a driver ready. Download the latest Realtek RTL8159 driver before you need it, especially if you plan to use the adapter on a machine with no other internet connection.
  4. Use a quality cable. The included short cable is fine, but if you need a longer run, pick a certified USB 3.2 Gen 2×2 cable—not a generic USB-C charging cable.
  5. Test your whole chain. Your NAS, switch, and cabling all need to be 10GbE capable. A single Cat5e link or a gigabit switch port will bottleneck the setup.
  6. For sustained server use, consider a PCIe card instead. This adapter is best for intermittent, portable, or temporary high-speed connections.

At a street price of $89, the SKN-U310GT doesn't ask for a painful investment. But it does ask for a compatible host and a bit of setup homework.

What's next for portable 10GbE

The Realtek RTL8159 is an early signpost. If it proves reliable and cheap, expect a wave of similar adapters from other brands, driving prices even lower. Switch makers could respond with more affordable 10GbE desktop switches that make multi-gig the new norm for home offices and small studios.

Two things need to improve for wider adoption: driver availability and USB port labeling. Microsoft could include an inbox driver for the RTL8159 in a future Windows 11 update, making the adapter truly plug-and-play. Laptop and motherboard vendors could label USB-C ports with their actual speed—not just a generic symbol—so buyers know what they're plugging into.

For now, the SKN-U310GT stands as proof that portable 10GbE is not only possible but practical on the right Windows hardware. It's no longer a question of if you can take 10-gigabit Ethernet on the road, but whether you've got the port for it.