wifi 50% slower than ethernet

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › wifi 50% slower than ethernet

1101

3122 posts

Uber Geek

#271762 26-May-2020 11:08

Hi .
Just wondering

Is it normal for wifi to be approx 30% to 50% slower than ethernet , when its no where near wifi theoretical max ?
Tested via OOKLA speedtest
Tried a PC & notebook.
Tried ISP's default router & Unfi AP
Tried both 2.4 & 5.8

It was VDSL, so
The wifi download speed was much less than theoretical wifi max, so the wifi should have been able to max out at the same speed as via ethernet

Im just wondering whats going on, the wifi download speed was more than enough , just much less than via ethernet

hio77

12999 posts

Uber Geek

ID Verified

Trusted

Lizard Networks

#2491659 26-May-2020 11:14

Yes.

Wifi is generally half duplex compared to full duplex on ethernet. Ontop of that it's a shared medium and impacted by the enviroment around it.

#include <std_disclaimer>

Any comments made are personal opinion and do not reflect directly on the position my current or past employers may have.

freitasm

BDFL - Memuneh
79314 posts

Uber Geek

Administrator

ID Verified

Trusted

Geekzone

Lifetime subscriber

#2491661 26-May-2020 11:15

Have you checked for interference in your environment?

What router do you have and what WiFi type is being used (802.11 a/b/g/n/ac)?

What's the testing device? What type of WiFi adapter is being used and does it match the router type?

What is the band with being used (40/80)?

ShinyChrome

1575 posts

Uber Geek

ID Verified

Trusted

#2491662 26-May-2020 11:17

Sounds pretty normal, lots of factors play in here: signal attenuation from environmental factors/distance from AP, number of antennae in devices etc.

What sort of WiFi cards do the PC and notebook have?

1101

3122 posts

Uber Geek

#2491703 26-May-2020 11:32

I didnt spend much time testing, as the wifi speed was still more than good enough for what was needed .

AP's & PC/laptop in the same small room , nothing blocking signal
Tested on PC & laptop , whatever onboard device wifi they had
Tested on 2 wifi AP's , incl Unifi AP . I'd assume the Unifi should be more than good enough
801n & 5.8Ghz
5.8Ghz was clear from other channels/neighbors etc . House build blocks wifi , so any external interference would be negligable

Half Duplex : would that only halve the throughput link speed ? So if download is significantly less than wifi link speed , would half duplex still drop the download speed
Wifi OOKLA speed test maxed out at APPROX 35Mbs

ShinyChrome

1575 posts

Uber Geek

ID Verified

Trusted

#2491718 26-May-2020 12:11

1101:

Tested on PC & laptop , whatever onboard device wifi they had
Tested on 2 wifi AP's , incl Unifi AP . I'd assume the Unifi should be more than good enough

Depends on what sort of TX/RX capabilities either has, but a client will most likely bottleneck before the AP (I'm guessing it is something like a Unifi AC). If they are low-end devices, they could be cheaper 1x1 radios. Not that that is even close to the full story, as the others have said.

Try checking the client wifi connection speed as per here to see what the router/AP <-> client connection is like.

How many other devices are contending for air time in your house?

1101

3122 posts

Uber Geek

#2491733 26-May-2020 12:28

Wifi OOKLA speed test maxed out at APPROX 35Mbs
I dont believe thats anywhere near the max over wifi , on all devices/AP's .

I doubt that both laptops/PC & both AP's would max out at approx 35Mbs , incl on 5.8Ghz . (All tested individually)
2.4 or 5.8 made no real difference .

Im not going back to have another look , its more than OK as is (in that room).
Just wondering why .
nothing else was connected to 5.8 .

Would wifi's 1/2 duplex be 1/2 duplex only between adaptor & AP, or 1/2 duplex all the way out into the internet (that would explain it I guess)

antoniosk

2358 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#2491734 26-May-2020 12:29

Also, a good chunk of wifi ‘bandwidth’ will be taken up with error correction and retries, so the true net throughput to your machine will be lower as well

________

Antoniosk

Sharesies

Trade NZ and US shares and funds with Sharesies (affiliate link).

sm1ff

122 posts

Master Geek
Inactive user

#2491820 26-May-2020 14:03

Our ethernet speed is 900mb and I'm only getting around 200mb on wifi on my phone... so yeah

Mehrts

1063 posts

Uber Geek

Trusted

#2491987 26-May-2020 17:56

To determine whether any bottlenecks exist within your LAN & wi-fi equipment, use a basic bit of software called iPerf to generate network traffic from one device on your network and send it to another.

You run the "server" mode on a computer which is capable of delivering gigabit throughput, and then you run the "client" mode on another computer which can be connected either via Ethernet or wi-fi to to the network.

See the attached picture which shows the results of an iPerf test over Ethernet & wi-fi carried out on a MacBook Pro.
Wifi was provided by a Ubiquiti Unifi AC-HD In-wall access point which is a 4x4 MIMO device, while the MBP is a 3x3. This would be considered near the upper real-world limit of wifi speed.
Ethernet is practically double that, as you'd expect since wi-fi is only half-duplex i.e can only transmit and receive at separate points in time.

The half-duplex point only exists between the AP and the wireless client.
For example using the picture above, if your internet speeds were 200Mbps up & down, you *shouldn't* notice any difference whether connected via wi-fi or Ethernet providing you had good wi-fi signal and your client devices are capable of those speeds.
However if your internet speeds were, say 700Mbps up & down, then your wifi would become the bottleneck.

Wi-fi ≠ Internet. Which a lot of Joe Bloggs just don't understand.