SER9 Pro Wi-Fi interference issues

snackbar

Dear Beelink Support Team,

I am writing to report a severe hardware/shielding interference issue regarding my Beelink SER9 Pro mini PC (B255H5BF20658), specifically when used in combination with the Beelink Mate (Mate SE-A 9y.004610801N20) expansion dock.

To eliminate any OS or driver-related variables, I tested the machine under both Windows and a Fedora Linux Live USB, producing identical results. The router used is a TP-Link Deco (Wi-Fi 6E) placed directly next to the PC.

Here are the exact speed test results based on the configurations:

Scenario 1 (Worst): SER9 Pro placed on top of the EX Mate dock, using a HDMI connection.

Result: Wi-Fi is heavily choked. Speed drops to 10–12 Mbps Download / 5 Mbps Upload. High latency and unstable connection.

Scenario 2 (Partial mitigation): SER9 Pro placed under the Mate dock (dock is on top), using a DisplayPort connection.

Result: Performance improves but remains heavily bottlenecked at 100 Mbps Download / 8 Mbps Upload.

Scenario 3 (Flawless / Baseline): SER9 Pro used WITHOUT the Mate dock, connected directly to the monitor via USB-C.

Result: Wi-Fi works perfectly, hitting 430 Mbps Download / 28 Mbps Upload (which is my ISP’s maximum wire speed limit).

The Dilemma:
The EX Mate dock completely occupies the rear Type-C port that could otherwise provide a clean video output and flawless Wi-Fi. When the dock is attached, I am forced to use HDMI or DP. The physical presence and internal component noise of the Mate dock—combined with these video outputs—creates severe electromagnetic interference (EMI) that ruins the wireless transceiver’s performance.

Since this is clearly an engineering/shielding issue between the SER9 Pro and its official accessory, please let me know what hardware revision, updated shielding solution, or official fix Beelink can provide for this setup.

Looking forward to your prompt response.

Best regards,

Beelink CS-June

snackbar

Hello there,

Sorry for the trouble.

Could you please send us a picture of SN code(two lines) at the bottom of machine ?

Please repeatedly press delete key as soon as you turn on the PC, go to BIOS. Please send us a picture of the Main page, we will check if you need to update the BIOS.

Have a nice day~

snackbar

Hi!

After doing some extensive testing with different configurations, here are my observations regarding the Mate SE:

The worst-case scenario: The issue is at its absolute worst when the Mate SE is in the bottom position with HDMI connection to a monitor. The wifi is almost useless.

The best-case scenario (with a catch): Interestingly, when using the MATE on top position with DisplayPort; the performance seems quite stable—almost within an acceptable margin of error. However, this only works as long as the router is placed directly next to the device. If the router is moved away, the issue returns.

The baseline: The PC works completely fine on its own via a direct USB-C connection without the Mate SE.

The problem definitely seems to lie somewhere within the dock’s positioning and specific port combinations (especially bottom position + HDMI).

I wrote to the support team as well, they forwarded my case to the R&D team.

Beelink CS-June

snackbar

Hello there,

Your machine`s BIOS version should be the lastest.

So at present, it is recommended that you wait for the developers to provide the corresponding solutions.

Have a nice day~