My wifi often doesn't operate at the capacity that it should be. My online games often lag or freeze up and I have often to restart my router just to get things working.
What is the brand and model of your NAT router?
If you have more than setup, say so and include network layout from the DSL modem Inward. Not from the phone line to the NID and beyond.. (The NID is where all of the phone lines connect where one side is for the consumer and the other is for the teleco.)