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I know that:

  • the theoritical limit of 802.11n Wifi is 450 Mbps in the 5Ghz band (that I use),

  • the router reports a 450 Mbps speed (using nirsoft's great tool WifiInfoView)

  • Windows reports a 300 Mbps connection which is the max for my Thinkpad laptop 's Intel Advanced-N 6205 WiFi adapter:

    enter image description here

but in a more "practical use", what is the maximum typical speed possible with a 802.11n WiFi adapter, during a local network file transfer using "shared folders"?

The max I can get is between 20 and 25 MB/sec on average, which is far from 37.5 MB/s (300 Mbps) or 56 MB/s (450 Mbps). Which kind of numbers do you typically get?

As a comparison, if both computers use an ethernet cable, I reach 110 MB/s, which is very close to the 1 Gbps limit of my ethernet adapters + router + cables.

Example test:

  • computer B is plugged with a 1 Gbit ethernet connection to the same router, and has a 1 GB file in a Windows "shared" folder (disk=SSD)

  • we download this file from computer A using Wifi

(A similar question for USB is: What's the maximum typical speed possible with a USB2.0 drive? )

Basj
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  • I have an Intel 8260 AC card on this machine and typically get 55 to 60 Megabytes/Sec transfer over the LAN. Try updating the router firmware and also the wireless driver. – John Nov 24 '20 at 13:10
  • @John [Intel 8260 AC](https://ark.intel.com/content/www/fr/fr/ark/products/86068/intel-dual-band-wireless-ac-8260.html) supports [802.11ac](https://fr.wikipedia.org/wiki/IEEE_802.11ac) which is more recent and a lost faster (800 Mbps in certain conditions) than 802.11n. – Basj Nov 24 '20 at 14:31
  • The N card will give the speeds you are getting (understood) and I was giving you an example. But try the updates as I suggested. – John Nov 24 '20 at 14:34
  • @John the hardware of my WiFi card (https://ark.intel.com/content/www/fr/fr/ark/products/59471/intel-centrino-advanced-n-6205-dual-band.html) does not support WiFi "ac", "n" is the max it does (300 Mbps). – Basj Nov 24 '20 at 14:37

1 Answers1

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The answer is a combination of many factors.

Basically the slowest factor in the mix will give you the speed.

If the wifi card is slower than the router, the wifi card speed is not surpassed. If you copy a file on a slow HDD, and that speed is slower than the wifi, then that decreases the speed even more. If your computer is very busy and the maximum speed is brought down by that, or if the wifi is very busy at that moment, it can also slow things down.

So the maximum theoretical speed is the maximum speed of the slowest device in the mix under optimal conditions. So lets assume that your computer is faster than the wifi speed of 300mbit your wifi card supports, then 300mbit is the fastest maximal speed you can get. A different laptop with a faster wifi card could reach the 450mbit under optimal conditions.

LPChip
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  • Yes, the slowest element in the chain gives the speed, I should have mentioned that I use a SSD on both computers, etc. and that if I only replace WiFi by cable I have 110MB/s under the same conditions for everything else. My question was more: *even with a theoretic 300 Mbit/s (for the slowest element in the chain), we don't get 300/8 = 37.5 MB/s for file transfer, which speed do you typically get?* (again SSD write speed is negligible, I even used RAMdisks for my tests, etc.) – Basj Nov 24 '20 at 14:35
  • Wifi can be jammed by obstacles, signal strength and distance. If these are not optimal, speeds drop. If these are optimal, the advertised speeds is what you usually get, given which device is the slowest. these factors are usually at play, so there is no answer to what it usually is. It really depends on the situation. An Ethernet cable connection is always going to be around its designed speed unless the cable is broken or something is misconfigured. Also, a bad wifi driver can cause slow wifi speeds. – LPChip Nov 24 '20 at 14:46