Slow Wi-Fi LAN speed

Question

I have PC, laptop and router (ASUS RT-N10U). PC has wired connection and laptop wireless. When I transfer files from my PC to laptop, the speed is only 3MB/sec. I tried to switch wi-fi modes on router (b/g, n) but it was not helpfull. Also i check the distance factor (physically bringing the laptop to the router) and it was not helpfull also. What may be the cause?

Answer 1

Your connection speed is 54Mbps so you're probably connecting with the 802.11g protocol.
Then the 3MB/s is the expected speed. Ideally you would get to around 3.5MB/s but that would be the absolute maximum.

Have a look at this site.
There ~20Mbps downstream is mentioned. (just ~2.5MB/s)

Please note the difference in Mbps (Mega-bit/s) and MB/s (Mega-byte/s).
Your 3MB/s is (x8) 24Mbps.

You can also look at this answer. It has some lovely technical explanations.

In real world conditions I'm happy as long as it's over 15 megabits/sec. (1,8MB/s)

The rule of thumb for 802.11 is that you can get TCP throughput of 50-60% of the signalling rate you're getting, and you only get the best signaling rate under the best conditions.

So 50% - 60% of 54Mbps is 3,3MB/s - 4MB/s

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Now for the (maybe) good news. Your Atheros AR9285 should be 802.11n capable. Your ASUS RT-N10U should also be a 802.11n router so if you connect with 802.11n the speed should be higher. (Your router goes up to 150Mbps, so not really the actual 11n standard but it might be a bit faster). But if your router is in 802.11-a/b/g/n mode it will connect much slower (somehow 11g and 11n don't mix well). If you don't have devices which need 802.11b or g, set the router to 802.11n only.

If you get a link-speed of just 64Mbps after doing this, switch back to 802.11g only because you'll only get an unstable connection this way (and you'll need to live with 3MB/s or buy new hardware). If you get a link-speed of 150Mbps you should see a much higher throughput.

Answer 2

A variety of factors will affect transfers like this, and network quality is not your only issue. Here's some possible problems:

• slow storage devices. Are you transferring to/from a slow USB stick or SD card?
• Protocol overhead will slow down your total transfer rate when you're working with small files. Try using tar or zip to compress your files first
• excessive disk use on either machine will slow things down. If you're running a backup engine like Crashplan, that could be burning your bandwidth

Here's a few diagnostics you can try:

• do an internet speed test from both your machines to the internet (http://speedtest.net). If both machines have a nice, fast uplink, then you know the router isn't to blame, as your machines can connect quickly to the Internet.

Answer 3

Check your routers advanced wireless settings for "Enable 20/40 MHz Coexistence" or something similar. Uncheck the box as it will cut the 2.4ghz channel connection speed between your wireless card and router in half. :)