WiFi Speed Question

[Mistafishman]

I have a Gigabit Up and Down plan in my apartment and get usually at least 800 Up and Down when wired into the wall our router which is more than fast enough for me. I’m confused that my WiFi speeds on my phone and laptop are not that fast (comparatively). I get ~80 Down and ~170 Up. I have an iPhone 12 and a cheaper (~$70) TP-Link router. I get roughly the same speeds on my Dell XPS. I’m on a 5GHz channel using WiFi 5 (802.11ac) since it doesn’t support WiFi 6. The router has 3 antennas. I use Ookla to test my speeds. I thought that WiFi 5 would have higher throughput even with bottlenecks that most connections inevitably have. If anyone is more knowledgeable about this I would love to know.

PS, I have gotten the same results on various different firmware updates on the router and OS updates on my devices.

[WereCatf]

20 minutes ago, Mistafishman said:

I thought that WiFi 5 would have higher throughput even with bottlenecks that most connections inevitably have.

Yeah, that's not quite how it works.

 

For one, if e.g. your router supported 866Mbps speed on 802.11ac, a connected device would practically only get half of that speed, because WiFi is not a duplex-medium, it's a simplex-medium; you can only send or receive, not both at the same time. Secondly, the connecting device itself also has to support 866Mbps over WiFi. It's not enough for only the router or only the device to support high speeds -- they BOTH have to. Thirdly, practically all WiFi-router-manufacturers lie about their maximum supported speeds by calculating 2.4Ghz-speed + 5GHz-speed and reporting that as the router's speed -- that's not how it works. Your device will only operate on one or the other frequency, not both of them at the same time.

[Kilrah]

Cheapo routers/APs also lie in the sense that they might support accessing the media (RF) at some rate, but not actually be able to transmit/receive data at that rate due to bottlenecks somewhere else in the router's system. Kinda like having a gigabit LAN and accessing a fast SSD but through USB 2.0... you'll still only get 160Mbps.

 

I've got a high end WiFi 6 router, and while my phone doesn't support WiFi 6 I still get 400Mbps over WiFi.

[Mistafishman]

1 hour ago, WereCatf said:

Yeah, that's not quite how it works.

 

For one, if e.g. your router supported 866Mbps speed on 802.11ac, a connected device would practically only get half of that speed, because WiFi is not a duplex-medium, it's a simplex-medium; you can only send or receive, not both at the same time. Secondly, the connecting device itself also has to support 866Mbps over WiFi. It's not enough for only the router or only the device to support high speeds -- they BOTH have to. Thirdly, practically all WiFi-router-manufacturers lie about their maximum supported speeds by calculating 2.4Ghz-speed + 5GHz-speed and reporting that as the router's speed -- that's not how it works. Your device will only operate on one or the other frequency, not both of them at the same time.

Thank you very much! I don’t know too much about networking and this was very informative!

[Lurick]

Additionally to what @WereCatf said each antenna is limited as well. On WiFi 5 (AC) devices each 5GHz antenna can do roughly 433Mbps (iirc) so if your client device is only 1x1 then best you'll see is around half that. If it's a 2x2 setup then you'd probably get somewhere around double that best case. Most phones are 2x2 but some older phones might only be 1x1 or even worse, 1x1 and limited to WiFi 4 (802.11n) (some on 2.4Ghz only even). Transmit x Receive antennas in the device is what the numbers stand for so 3x3 would be 3 transmit and 3 receive antennas in the host device.

The router also can have a similar setup, some might say 2x2 + 1x1 (or similar to that) where they will talk to 1 client with 2 antennas and the others with the remaining antenna, or some combination of 5GHz off the 2x2 and 2.4GHz off the 1x1 for example.