I have this new Archer C54, this problem start after i was enabling QoS.

At first i was curios what it does, then after i know what it does i instantly disabling this feature.

But the problem start here, my dad laptop wi-fi speed capped at around 2-3Mbps, checked with LAN but i got normal speed (80-100Mbps).

I checked my laptop, it's normal. No problem with the capped speed. Checked all smartphone connected to 2.4Ghz wi-fi, still normal also with the 5Ghz.

The next day this problem happen to my laptop (same capped speed). Checked the connected smartphone again, but still normal no capped speed. Same with LAN, it's normal.

Does this both laptop also had slow speed with other wi-fi? No, even after the first installation this Archer C54, we both got normal speed.

Now, what i already did was :

- Factory Reset (useless)

- Upgrade Firmware (useless)

- Reinstalling/Update Wi-fi Driver (useless)

- Reinstalling windows (the stupid thing i've tried, and still useless)

- Changing bandwidth to 20Mhz or 40Mhz (useless)

- Changing channel (useless)

- Parental controls? no any configuration

- Re-enabling-disabling QoS (useless)

- Changing LAN cable to my main router (useless)

I also noticing that it's possible to got normal speed just by re-enabling/disabling my laptop wi-fi, but it's so rarely.

Also after a few second or minute i connected with the normal speed it's 100% will reconnected from my wi-fi and back with the capped speed.

On windows settings it's also says my network link speed only 144/72Mbps with the capped speed, while i got 300/150Mbps on other wi-fi/normal speed.

*Summary :

- Problem only happened to connected laptop with 2.4Ghz network.

- All smartphone connected to network (2.4Ghz/5Ghz) got normal speed.

- All laptop got normal speed with the LAN/other wi-fi network.