wndr3300 looses mbps by half

Dual band refers to the frequency bands - 2.4 & 5 GHz - the g & n are WiFi specifications or standards. 802.11g allows a connection on the 2.4GHz band only at connection speeds up to 54 mbps, 802.11n allows for connections on both bands and connection speeds of up to 600 mbps. I want to make it very clear that when the standards specify a connection speed, the use the words "up to", which indicates this is a maximum possible speed and not necessarily the speed you will connect at, or even should expect to connect at. Pay attention also to the words "allow for" - the 802.11n standard allow for many options, and this enables manufacturers to claim their equipment as compliant with the standard even though, because the equipment meets only the minimum requirements of the standard, it is incapable of delivering the maximum performance that the standard allows for. There are also options (for example encryption type) that may restrict performance - if you chose WEP as your encryption, that would prevent you from connecting at speeds higher than 54mbps - and configuration settings that may have similar effects. The sad state of affairs is that WiFi technology has become so complex that installing & maintaining a wireless network for is no longer a job for the technologically "un-savvy" consumer, and this is only going to get worse with the coming of the new 802.11ac standard. In my mind the time has come for the user to decide if they want to spend the time to learn the technology or spend the money for someone who has done so.