Question : Problem: 802.11n speed drops to 802.11g rate

I tried a Belking "pre"N wireless router with my Toshina Tecr A9 laptop which has a 802.11n card.
If I changed settings, channels, etc, I would get the higher connectivity (130 Mbps or so) for a few minutes, but it would eventually fall back to the 802.11g (54 Mbps) speed.
I am in the same room as the router, so interference shouldn't be the issue.
I then tried the same with an Apple AirPort Extreme.  Same issue.
Since there are other computers connecting at the 802.11g speed because of their hardware, does that knock all connection speeds down to the slower rate?

Answer : Problem: 802.11n speed drops to 802.11g rate

Normally a router will drop to the speed of the slowest active connection for all other devices attached to it. Modern routers, mainly those that have multiple aerials, can keep up the high speed even if a low speed device has connected. Also, "n" mode is at the moment no proper standard yet. This means that each manufacturer has it's own standard and therefore if you connect a Wireless NIC which is capable of "n" speeds to an access point that can also run at "n" speeds, you usually will get compatibility problems if they are from different manufacturers, and that can cause the speed to drop too. Then as a further drawback, many routers that boast 802.11n don't yet have the best firmware, so they often just don't function like they should. Sometimes a firmware update can help.