Why is my wireless so slow compared to my wired download speed?

Question

I just used speedtest.net (using Firefox) to compare my wired connection speed with my wireless connection speed. With my current contract (with Videotron), I'm supposed to get

• Download speed: 8Mbps
• Upload speed: 1Mbps

Here are the results of the speedtest.net test:

Wired

• Ping: 14ms
• Download speed: 8.41Mbps
• Upload speed: 1.04Mbps

Wireless

• Ping: 16ms
• Download speed: 0.18Mbps
• Upload speed: 0.98Mbps

The difference in download speeds seems staggering to me since I did the test 1 meter aways from my router.

Any clue as to why my wireless download speed is so low compared to my wired download speed?

using Ubuntu 11.04 on an Acer Aspire 5536-5519

Oh and it might be worth mentioning that my girlfriend has no trouble at all with her wireless connection. No slowness at all. (She uses Firefox on Windows 7 on a Dell) Here's the results for the same test on her system:

• Ping: 22ms
• Download speed; 8.44Mbps
• Upload speed: 1.02Mbps

Answer 1

There are many different factors that affect wireless speed, too many than can be summed up in a paragraph. PC Pro has an article on tracking down what affects your wireless bandwidth.

To find what is causing your slowdown, you have to start eliminating variables. Could it be your router? Try swapping your and your girlfriend's routers. It could be your hardware, do you get better speed at your girlfriend's place? "Security" software can also significantly lower your bandwidth; try disabling it (temporarily) for testing.

Congestion? Start unplugging (not just switching off) electrical devices like wireless phones, microwave ovens, fluorescent lights, televisions, et al. and retest after each one. Find what frequency or channel your router is operating at, and switch it. Multi-path interference? Move your router or laptop around, take down mirrors (yes, I'm serious).

It's very unlikely a single thing is causing your slowness, you have to test every possible problem, then fix it. Don't stop after the first change that seems to work.

Answer 2

As another machine fairs far better under the same circumstances I would suspect either driver issues or a hardware fault.

It would be worth looking up the laptop's wireless chipset and seeing if other report problems with it under Linux, though I think a hardware issue is more likely (as the wireless driver situation is usually "it works or it doesn't" rather than "it works reliably but very slowly").

As the card is working but not well, the most likely issue is the antenna. As your upstream speed is not badly affected (being around the expected speed for your line) but the downstream is your wireless adaptor has one dysfunctional antenna and one that is fine. The borken one could simply be a lose connection, though you may not be able to do anything about that. If the antenna it internal to the wireless adaptor there is nothing you can do but replace the whole adaptor. If the antenna connects to the card you might be able to replace it (for fix the connection if it is just disconnected). For instance this is the mini PCI-E card that AA1 uses:

You can see the connections for the antennas which are apparently replacable (several places list spares as available, like so).

Of course if there is a hardware issue, turning off the internal adaptor and replacing it with a USB one would be easier than hacking around inside the machine!