I have a NetGear DG834B modem router with an ADSL connection on the ground floor. On the 1st floor, I have acceptable connections from my Windows desktop PC, Macbook Pro, iPhone and iPad. However, the Mac Mini (intel core 2 duo), which serves as media centre, has constant speed problems -- endlessly buffering or sometimes failing to play internet video. (Although it never fails to connect to the wireless signal.)
All my computers report different speeds using http://www.speedtest.net. The router reports a downstream connection speed of 18461 kbps, but on the various computers using speedtest.net I get from a maximum of around 10Mbps (PC) down to under 2Mbps (Mac Mini).
Does the Mac Mini just have a weak antenna? Would the problem be cured by something like this? http://www.amazon.co.uk/Netgear-Universal-WiFi-Range-Extender/dp/B003LAD8BY
Or perhaps upgrading the router to an 802-11n device?
Duplicate problem here, but none of the advice there worked for me: Mac Mini's internet very slow, every other device fine (PC, iPhone, Xbox 360)