If you're talking about the Internet, it's the same speed. Wireless card speed can now reach 54 megabits, although the wired can reach 1000 megabits, but your broadband speed (telecommunications, Unicom) is only 4 megabits. So if it's 4 megabits, the speed on the connection is the same.
If you just send files over the Intranet, of course, wired will be faster than wireless.