Well, it depends...if ur phone phone supports dual band, using a dual band on ur router might get you a good speed but only of you are close to the router...the d/ce b/n single and dual band is that single was weaker signal but it's long range and double has strong band but it's only short range so if u'r close to the router use dual band and first make sure ur device supports that go to gsm arena for ur phone specs and look under wifi:- if it says a/b/g/n/ac then it's dual band but if it says a/b/g/n (no "/ac") then ur device supports only single band and there is no point on using dual bans on ur router