Wifi is limited by so many factors. single band, dual band, AC band.
one is 2.4 ghz, the other 5ghz . Main difference is the frequency divisions of 20mhz, 40mhz and 80 MHz respectively for them. Maximum speeds are known to be 65mbps, 130mbps and 200mbps onwards for AC band. It depends on the how dirty the radio band is.
Wired means you need to run LAN cables called RJ45 cat 5e or cat6 from the router / switch to your computer. The standards is FE or fast Ethernet which is up to 100mbps, GBe or 1 gigabit per second (some goes even up to 10gbe ports on servers)
To get the subscribed speed, LAN CABLE IS NEEDED for over 100mbps. It guarantees stability.
The quality of TP splicing and patch cord is also important.
So don't complain if you get 30mps if you are using a wireless-G standard as that is the max speed on your galaxy Tab