Wireless Joint

Best bet is to search for what modem it has. If they are cheaper devices more than likely category 4 or 6. Far as speed differences could also be band connection. If one modem has a band frequency the other doesn't have or just naturally connects to the faster band. Here is a video about why ...

Lookup the modem category of the device. If one is a higher category modem than the other and is the faster one, that is your answer. Also make sure your signal levels match when comparing. Sometimes the devices will also connect to different towers even when you don't think it could. That is if ...