Bug Report: QoS Still Broken in Wireless Only on Latest Firmware (v1.4.1 / v1.5.0) – Archer AX12
Hello TP-Link Dev,
I wanted to follow up on my previous thread regarding the ongoing QoS (Quality of Service) issues on the Archer AX12. While it’s great that this router finally received a long-overdue firmware update (maybe this is a cheap router so they actually don't care), my testing shows that the underlying QoS bugs have unfortunately not been fully fixed.
I have extensively tested both recent firmware versions (v1.4.1 and v1.5.0) under a bridged PPPoE setup (100 Mbps ISP connection), and here are the results of my findings:
The Issues Found:
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5GHz Wireless Mode (QoS Completely Ignored): When connected via 5GHz Wi-Fi, the QoS rule fails entirely. A speed test will bypass the limit and pull the full 100 Mbps line speed even if I set QoS to 90 Mbps.
The Impact (Bufferbloat & High Ping):
Because the 5GHz band ignores the QoS limit, any client performing heavy tasks (like running a speed test, downloading files, or streaming high-quality video) completely saturates the bandwidth.
The AX12's QoS engine is simply too slow to detect sudden heavy traffic loads, resulting in:
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Severe bufferbloat
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Massive ping spikes/lag for other network users, destroying the gaming experience.
Note: The reason I configure my QoS to 90 Mbps on a 100 Mbps line is specifically to leave a 10% overhead buffer to prevent this exact latency spike—but the router is currently failing to enforce it properly on wireless clients.Hoping the dev team sees this and pushes a real fix cheers.
To clarify, the general network performance on the latest firmware is actually quite good, whether QoS is enabled or not. The QoS feature itself works exactly as intended over an Ethernet connection—when I set the limit to 90 Mbps, it successfully prevents the wired device from pulling the full 100 Mbps. This is great because it leaves a 10% overhead buffer to keep pings low and stable.
However, the issue is strictly with the 5GHz wireless Wi-Fi.
When i testing on 5GHz Wireless, the QoS limit is completely ignored, and clients always pull the full 100 Mbps line speed. This means if a wireless user starts downloading files or streaming 4K video, they will consume the entire bandwidth. Because the router fails to enforce the limit on wireless devices, it leads to massive bandwidth saturation, high ping spikes, and severe bufferbloat for everyone else.
In short: QoS does a great job on wired Ethernet, but it is broken and completely bypassed on the 5GHz wireless band.
QoS Settings :
Wireless Mode :
Ethernet Mode :
