Should you turn on the WMM router or not? I turned it off once, and the whole house's WiFi dropped from 300 Mbps to 54 Mbps

incident happened last month. I was looking for advanced wireless settings in the AX3000T backend, looking for channel settings, and casually saw a switch called WMM, with the status set to on. My mindset at the time was very typical: if you turn off a switch you don't know, try it—maybe it can even 'streamline the system.' After turning it off, I didn't notice anything that night. The next day, my family was casting in the living room, which got stuck as a PPT. My phone's speed test dropped from just over 300MB to a cap of 54MB, and all five phones did this.

spent half an hour trying to connect these two things. This article will explain everything at once: what WMM is, why it can't be turned off, and what those online claims about 'turning off WMM to fix game lag' all at once.

first, what is WMM: the sorter in WiFi

WMM stands for Wi-Fi Multimedia, which you can think of as the sorting rules for packages within WiFi. All the data packets on home devices come out through the router port. If you don't queue, you'll step on each other's faces: you're downloading movies, your girlfriend is video meeting with clients, the packets are crowded together, and the video ends up freezing.

What

WMM do is prioritize data packets, with four teams in total:

note: software download traffic is by default to the backend queue, with the lowest priority. That's why you can still play mobile games while watching movies—not because your internet speed is enough, but because WMM has pushed downloads to the back.

the result of turning it off: the whole house dropped back to 54 trillion

back to the time I was careless. After turning off WMM, the speed test showed all five phones capped at 54MB, with no extra touch. This number is not random—54Mbps was the highest speed during the 802.11G era, the standard in 2003.

why would turning off a "multimedia switch" revert the speed to twenty years ago? Because the WiFi Alliance has a strict rule: all high-speed speeds after 802.11n (including WiFi 5 and WiFi 6) are only allowed to use when WMM is enabled. WMM is a prerequisite for this high-speed mechanism. If you turn it off, the router will only dare to use the outdated 54Mbps data transmission, regardless of whether the device supports WiFi 6.

I later tried it on an old Mercury back home, and the problem was exactly the same: turning off WMM, both 2.4G and 5G dropped to 54MB. So this isn't a Xiaomi bug, it's an industry rule. Who designed this switch? If you turn it off, you're crippled, and you just leave it there to make people click it. Most of the time, it's a legacy for compatibility with boss cards from before 2008; keeping it now is just a rip-off.

By the way, if your home speed test is currently stuck around 54Mbps, don't suspect your broadband is in arrears—check the backend to see if someone has turned down WMM. The entry point is usually at 192.168.1.1 (or your brand's corresponding address) in the wireless settings and advanced settings layer, called WMM or WMM APSD.

rumors circulating that 'turning off WMM to fix game lag' really makes people think it's effective

many old posts online teach people to "close WMM when the mobile game lags," and some people actually say the game runs smoothly in the comment section. At first, I was suspicious too, but later I figured out the trick was going on.

you turn off WMM, all your devices in the house drop back to 54MB—including the computer that kept downloading in the background and the sync cloud drive running on. FamilyMart's total traffic was forcibly squeezed below 54 trillion, so the empty data was no longer squeezed out, but the game's small data packets ended up in the queue. So "smoothness" is real, but the price is a whole-house slowdown. You trade your parents' streaming speed for the same latency as your own—this is robbing Peter to pay Paul.

When

is really lagging, what you should check isn't WMM:

• first check who is competing for bandwidth: in the router's backend device list, you can see the real-time speeds of each device. Last time at my home, the TV box secretly updated firmware in the background and consumed 180MB.
• checking the channel: 2.4G is crowded on channel 13 with many neighbors. Manually fixed to 1 or 6, latency is immediate.
• devices: If you have more than thirty devices, don't expect old routers to deliver low latency.

rule out all three steps before considering anything else. I previously wrote a detailed article on channel interference and interference investigation processes. In the WiFi of the self-inspection article on channel interference, the method for locating bandwidth was described in the article on speed testing that does not meet standards.

where are the switches of each brand (it's normal not to find them)

I checked several machines I have and a friend's place, and the switch positions are roughly like this:

see, newer firmware simply hides or deletes this switch, and manufacturers know that keeping it will only rip people off. Xiaomi's approach is actually the best — simply not closing it off. So if you can't find WMM in your own backend, it's not because your eyesight isn't good—it's the vendor who has filled this gap for you.

there are two other switches in the backend that look similar to WMM, so don't confuse them: one is UPnP, which automatically maps to the tube ports, and that switch is truly valuable for security discussions; The other is WPS one-click connection , which I really recommend turning off. WMM is different from the other two; it has no security features, just a pure queue rule, so if you don't open it, it's not a good thing.

WMM What is APSD, and is IoT disconnection related to it

some backend switches are called WMM APSD. The extra APSD is a power-saving system that lets the phone sleep longer between sending and receiving data, mainly for battery life. This thing sometimes really causes trouble: I have a 2.4G camera I bought in 2017, but the firmware is old. It disconnects whenever it encounters APSD, disconnects every few minutes, and the logs say it's power-saving wake-up and not synced.

old smart devices frequently disconnect or no matter how hard you reconnect, you can try turning off APSD (note: the option to disable APSD, not WMM itself). My camera stabilizes after turning it off. This is the only scenario worth trying in the WMM system; otherwise, don't even look at the entire WMM block and keep it as default.

By the way, I wrote separately about troubleshooting smart device network setup and disconnections. In the article about smart device network failure failures, one discussed connection failure, the other about disconnection after connection.

Conclusion: Give a judgment order

following this order, you basically won't take detours:

sum up in one sentence: WMM is the ticket to FamilyMart's high-speed WiFi—if you close it, the whole house is ruined; Its included APSD power-saving can occasionally trap old devices, but that can be turned off separately. Except for these two situations, you won't need to look at this switch again in your lifetime.