M720q Ethernet Upgrade

I recently acquired a used Lenovo M720q.

It’s a 1 Liter Mini PC which I use as a local Home server.

I really enjoy it, since it’s quite fast and uses only little electricity.

The only issue I had, was, that it only has a 1 Gigabit Ethernet Port.

Since even normal hard drives can read and write sequentially with ~250 Megabyte/s, this is an obvious bottleneck, when using it as a filestorage.

Luckily, you can get 2,5 GbE Network Adapters on Aliexpress.

These little cards use a RTL8125 chipset from Realtek which should be supported from kernel 5.10 onwards.

While this is not the “best” chipset, it is quite cheap and when using the proprietary Realtek firmware (apt install firmware-realtek) it seems to work without issues.

So I replaced the Wi-Fi Card of the machine with one of these:

And the Ethernet Port also almost fits the bracket on the back:

So far I am quite impressed with these Cards.

• They are somewhat cheap (<20€ including delivery and taxes)
• They work out of the box on modern Linux distributions
• I can get a constant ~2.3-2.4 GB/s out of it

lspci output

# lspci -v -s 02:00.0
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller (rev 05)
        Subsystem: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller
        Flags: bus master, fast devsel, latency 0, IRQ 17, IOMMU group 10
        I/O ports at 3000 [size=256]
        Memory at b1100000 (64-bit, non-prefetchable) [size=64K]
        Memory at b1110000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: [40] Power Management version 3
        Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
        Capabilities: [70] Express Endpoint, MSI 01
        Capabilities: [b0] MSI-X: Enable+ Count=32 Masked-
        Capabilities: [d0] Vital Product Data
        Capabilities: [100] Advanced Error Reporting
        Capabilities: [148] Virtual Channel
        Capabilities: [168] Device Serial Number 01-00-00-00-68-4c-e0-00
        Capabilities: [178] Transaction Processing Hints
        Capabilities: [204] Latency Tolerance Reporting
        Capabilities: [20c] L1 PM Substates
        Capabilities: [21c] Vendor Specific Information: ID=0002 Rev=4 Len=100 <?>
        Kernel driver in use: r8169
        Kernel modules: r8169