Jeff upgraded to 50mbps download, but he doesn't get that. Leo says that it's likely a "burst mode," at the beginning, and then it slows down to a conventional speed. One thing Jeff can do is upgrade to an "N" speed router (802.11n).
He can test his speed at speedtest.net. He's currently getting 18Mbps down, which Leo says is probably more than enough and not unusual. The speeds also can vary between devices, so he may get slower speeds on his mobile device than on his desktop. That chatroom suggests that he set up his Wi-Fi network as WPA2 AES, because that's faster for mobile devices.