Flint 2 GL-MT6000 + MediaTek MT7925: high link rate but low Wi-Fi throughput

Router
1

Hi everyone,

I am trying to troubleshoot a Wi-Fi throughput issue with my GL.iNet Flint 2 / GL-MT6000 and a laptop using a MediaTek MT7925 Wi-Fi 7 adapter.

The issue is that the laptop connects with a high link rate, but real throughput remains very low compared with other devices and another router.

Setup

Router: GL.iNet Flint 2 / GL-MT6000
Firmware: v4.9.0 release
Client: ASUS ProArt P16
Wi-Fi adapter: MediaTek MT7925 Wi-Fi 7
OS: Windows 11 25H2
ISP: DU, ~1 Gbps connection

Baseline results

Wired Ethernet through the Flint 2 is excellent:

  • Laptop via Ethernet to Flint 2: around 941/937 Mbps

So WAN/routing performance seems fine.

Wi-Fi from another device is also good:

  • Samsung S24+ on Flint 2 5 GHz: around 832/416 Mbps

So the Flint 2 Wi-Fi is capable of high speed with other clients.

The same laptop also performs correctly on another router:

  • Laptop on Linksys MX56DU 5 GHz: up to 946/947 Mbps

  • Link rate on Linksys: 2402 Mbps

  • Same speed test server

Problem case

The same laptop connected to the Flint 2 5 GHz remains capped around:

  • ~170–195 Mbps download

  • ~60–195 Mbps upload, depending on MediaTek adapter settings

This happens even with strong signal and high negotiated link rates.

Examples tested on Flint 2:

Channel 48 / 160 MHz / TX High / AX enabled

  • RSSI: around -55 to -57 dBm

  • Quality: around 84%

  • Link rate: 2402 Mbps

  • Speed: around 188/61 Mbps

Channel 48 / 80 MHz / TX High / AX enabled

  • Link rate: 1201 Mbps

  • Speed remained around 190/61 Mbps

Channel 48 / 80 MHz / AC-only

  • Link rate: 1201 Mbps

  • Speed: around 165/67 Mbps

  • Worse than AX mode

Channel 128 / 80 MHz / TX High / AX enabled

  • RSSI: around -44 dBm

  • Quality: around 92%

  • Link rate dropped to only 286/286 Mbps

  • Speed: around 61/39 Mbps

So channel 128 is not usable with this laptop/client combination.

Laptop-side adapter testing

Initially, the MediaTek MT7925 had poor performance even on the Linksys router. I found a partial/final fix for that by changing the adapter settings in Windows Device Manager:

MediaTek MT7925 → Advanced

Current best laptop-side settings:

  • Mode: BE/default

  • 5 GHz bandwidth: Auto

  • RSC IPv4/IPv6: Enabled

  • U-APSD: Disabled

  • AMSDU Rx: Enabled

  • AMSDU Tx: Disabled

After reboot, this fixed performance on Linksys:

  • Linksys 5 GHz: 946/947 Mbps

However, the same laptop with the same fixed settings still performs poorly on Flint 2.

With Flint 2:

  • AMSDU Rx Enabled / Tx Disabled: around 173/195 Mbps

  • AMSDU Rx Disabled / Tx Disabled: around 177/170 Mbps

  • Default-like behavior: around 190/61 Mbps

So disabling AMSDU Tx improves upload somewhat, but the Flint 2 + MT7925 combination still appears capped around 170–200 Mbps.

Why I suspect a compatibility/driver interaction

This does not look like a general internet/router/laptop fault because:

  • Flint 2 Ethernet: ~941/937 Mbps

  • S24+ on Flint 2 Wi-Fi: ~832/416 Mbps

  • Laptop on Linksys Wi-Fi: ~946/947 Mbps

  • Laptop on Flint 2 Wi-Fi: only ~170–195 Mbps

  • Signal/link rate can be strong/high, but real throughput is poor

This looks like a specific interaction between:

GL-MT6000 / Flint 2 Wi-Fi stack + MediaTek MT7925 Windows client

Possibly related to aggregation/offload behavior, AMSDU handling, AX/160 MHz behavior, or mt76/MediaTek client compatibility.

Question

Has anyone else seen similar behavior with the Flint 2 and MediaTek Wi-Fi clients, especially MT7925 / Wi-Fi 7?

Are there any recommended advanced settings to test in LuCI / OpenWrt, such as:

  • WMM

  • Airtime Fairness

  • OFDMA

  • MU-MIMO

  • TWT

  • 802.11k/v/r

  • WPA2 vs WPA3 / PMF

  • mt76-specific settings

  • hostapd options

  • aggregation-related options

I can provide more logs or run specific tests if useful.

2

You could try wifi analyzer to find the best channel on android.

Besides that if you already tried wpa2 and not noticed much difference, what about other connected devices on wifi?

Do you have a device far away which may need its own AP?, so it does not take priority over other wifi connected devices?

As for the link speed, I'm gonna be honest but those values are only reported by the wifi card, yes I call it a card even though it is just a chip, there are situations the same chip is presented as wifi card in a pc or other device with stronger hardware.

What I mean is that what reported on the wifi chip as link speed does not account what the lifting of the cpu can do, the chip still needs to offload it to the cpu and that is why link speed and speed are two different distinctive things.

And then you have the wired backhaul also... maybe this isn't the best quality?, you often want to overload the quality a little if you want to max it.

But there can also be a network switch with a attached cable to its port but nothing connecting to it or flapping, sometimes the spammy behaviour of dhcp acks of a single device can lower the quality of the network very easily the logs can be usefull.

3

Thanks, but as I mentioned I tried several different ways of interaction between these two devices. Also used a different router to check where was the issue. It is only two devices using the wifi at the moment of the test (a) my mobile and (b) the laptop.

4

Can you try a clean install of the op24 version of the firmware or vanilla openwrt. This might be the easiest way to exclude incompatibility between firmwares.