I am sharing my wifi with a Linksys E2500 router, which allows you to name each frequency (2.4 GHz, 5.0 GHz) of wireless network a different name. A user told me that if each band has a different name, it does not allow his computer to connect to both bands simultaneously to double the bandwidth for his connection. He says he can connect to either network independently when they are differently named. How can a device transmit a data stream along two separate bands simultaneously?
This Netgear webpage says that a simultaneous dual band router (e.g. the Linksys E2500 router) has "Twice the bandwidth", vs. "Same bandwidth as single band router" in a selectable dual band router.
It also says, "Separate networks avoid interference" in a simultaneous dual band router, implying that the bandwidth for a given connection is not doubled by simultaneous connection to both bands.