The Complexity of USB-C: Analyzing Framework's 10G Ethernet Module

Jeff Geerling recently explored the intricacies of high-speed networking via the WisdPi 10G Ethernet Expansion Card designed for Framework laptops. While the hardware promises blazing speeds, the implementation reveals the often-confusing landscape of USB-C standards.

The Hardware Foundation

WisdPi has been iterating on 5 Gbps and 10 Gbps adapters for several years, utilizing modern Realtek silicon. Specifically, this module employs the RTL8159 Ethernet controller. While powerful, these chips are known for occasional performance quirks, particularly when running on Linux.

The module is designed for versatility, fitting into any Framework Expansion slot, including those on the Framework Desktop. However, because these slots rely on USB-C, a significant bottleneck emerges.

The Bandwidth Bottleneck

To achieve the advertised 10 Gbps throughput, the RTL8159 requires a USB 3.2 Gen 2x2 connection, which provides a total bandwidth of $20\text{ Gbps}$ .

Performance Benchmarks

Framework 13 (AMD Ryzen AI 5 340)

On Windows 11, the average real-world maximum reached approximately 9.4 Gbps.

Interestingly, Linux performance was slightly lower, which was unexpected given that Framework's documentation claims ports 1 and 3 support Gen 2x2.

Framework 12 (Intel 13th Gen)

Testing on the Framework 12 yielded mixed results:

Linux: Running lsusb confirmed a connection speed of 20000 Mbps (20 Gbps). However, iperf3 tests only peaked at 7 Gbps.
Driver Issues: Attempting to compile the official Realtek driver on Ubuntu 26.04 failed, likely due to the kernel version (7.x) being too advanced for the driver.
Windows 11: Using the default driver, the speed remained at 7 Gbps. However, after installing the specific Realtek driver, performance jumped to the expected 9.4+ Gbps.

Bidirectional Note: During heavy testing, the module achieved roughly 9 Gbps upload and 4-5 Gbps download simultaneously.

Thermal and Physical Concerns

High speed comes with high heat. Thermal imaging revealed that the bottom plastic surface of the module reaches temperatures near $\approx 70^\circ\text{C}$ .

~~This is perfectly cool to the touch.~~ In reality, this is hot enough to cause Toasted Skin Syndrome if held against the skin for prolonged periods—reminiscent of the thermal issues found in older MacBook Pros.

WisdPi's Official Stance:

"The plastic surface temperatures are in compliance with IEC 62368-1 temperature safety limits."

According to the manufacturer, the device is safe as long as skin contact does not exceed 10 seconds. Additionally, the module protrudes a few centimeters from the chassis, meaning it ~~is portable~~ must be removed before placing the laptop in a snug sleeve or bag.

Final Verdict & Recommendations

Depending on your needs, the choice between the standard and high-speed card is clear:

Feature	Standard Ethernet Card	WisdPi 10G Card
Max Speed	2.5 Gbps	10 Gbps
Price	$\approx \$ 40$	$\approx \$ 99$
Heat	Low	High ( $\approx 70^\circ\text{C}$ )
Fit	Flush	Protrudes

Buyer's Checklist

Do I actually have a 10GbE network infrastructure?
Will I be using the laptop on a desk (rather than my lap)?
Am I comfortable installing third-party drivers on Windows?
Do I have a loose-fitting laptop bag?

Bottom Line: For the vast majority of users, the 2.5 Gbps card is the smarter, cheaper choice. Only opt for the WisdPi 10G module if you absolutely require maximum speed and want to avoid using an external dongle.

Disclaimer: The unit reviewed was provided by WisdPi for testing purposes.