We have a Qwest Actiontec Q1000 DSL Modem. Qwest said the modem speeds are 40Mbps down & 20Mbps up. When we connect to wireless and run a speed test at like Speakeasy or Speedtest the download is a maximum 20 Mbps & upload is 10Mbps on average. The second we plug into ethernet the same speed test 40Mbps down & 20 Mbps up. We are running compatibility mode with 802.11n/g only.

Anyone know why the speed is slower on Wi-Fi? I figure if the download speed is 40Mpbs and I am connected to 802.11 G that is 54Mbps, I should be able to receive 40Mbps???

asked 08/21/2011 01:44

LeviDaily's gravatar image

LeviDaily ♦♦

3 Answers:
The further away from the router you are the lower the speed will be. Also, if there are more than one wireless devices connected you'll also get less speed. The encryption will further reduce the speed. And then interference from other devices using the same bandwidth. Sometimes it helps to try the different channels and then use the one where you get the best throughput. Another thing, if you only have devices with "n" standard you are connecting with, it would be better to change to "n" only mode.
rindi's gravatar image


Even though 54Mbps is the reported speed, with frame-encapsulation and backwards-compatibility-protection overhead, true maximum throughput of 11a and 11g is about half that (around 27Mbps)... WEP and WPA encryption can knock off another 10%-15% because both of those also include the passphrase in every packet; WPA2-AES encryption does not include the  passphrase in the packets.

Matthew Gast gives a good breakdown of the technical explanation on the O'Reilly web site at

Though that shows only 11a/b/g, the principles are the same for 11n in both 2.4GHz and 5.8GHz (i.e. expect real-world maximum throughput of about half the reported connection speed).  But even single-channel 11n should get you full use of your 40/20 Mb connection, with typical connections being 130Mbps (maximum 150Mbps, but not seen very often), and wide-channel maximum connection of 300Mbs (typical 270Mbps) would be overkill for just accessing that 40/20Mb internet connection... still, for LAN transfers, 40MHz-wide channels should be well-worth it.
Darr247's gravatar image


I agree with Darr247; however, most of my experiences with throughput and 802.11 is around 20Mbps utilizing TCP, slight better, 22Mbps with UDP. Additionally, rindi has a good point on range, your SNR and RSL (upstream and downstream) will dictate your actual throughput. So there are many factors at play that could be the issue.

rfc1180's gravatar image


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Asked: 08/21/2011 01:44

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Last updated: 09/07/2011 03:57