[kman42]

My father-in-law has a MacBook and he swears that his airport access is slower when he is running on battery power. I suggested that he may have just been in a different part of the house where coverage may not have been as good, but he says he's tried it both ways in different locations. I spent about five minutes with his computer and it did seem slower on battery, but I didn't have time to perform any real experiments. I switched his computer to perform better whether on battery or power in the Energy preferences. Anything else I might try?

[Railroader]

Speedtest.net - The Global Broadband Speed Test - use that site to verify.

[Tomchu]

An Internet speed test isn't going to measure WiFi performance, since people's Internet connections are almost always slower than their WiFi performance capability.

[Railroader]

Originally Posted by Tomchu 

An Internet speed test isn't going to measure WiFi performance, since people's Internet connections are almost always slower than their WiFi performance capability.

True dat. I don't know what I was thinking.

OP: What is your dad using the wifi for?

[ghporter]

It's quite possible that on battery power the Mac turns down the AirPort card's power, which could result in slower speeds.

To test the speed of the WiFi connection with battery or AC, set up a particularly largish file somewhere on your network (preferably on an AC powered, wired computer) and copy it wirelessly, first on AC and then on battery. Timing the copy action should tell you if there's any difference between the two situations.

[kman42]

That's a good idea. I'll try it next time I'm over. I was just assuming that if there were some sort of power saving, airport cutting feature that someone would know about it