Originally Posted by DarthAcer
Just an idea. If you have neighbours with 802.11n router running in 'n'-only mode that might really screw up all the 802.11g networks in the area. Alternatively, if your router is set for compatibility with 802.11b then a computer in a vicinity with 802.11b (even if it's not associated with router) will take down your throughput.
With that in thought, log into your router and change the channel that it is...