Minimum Connection Speed
Xbox LIVE requires a high-speed connection to take full advantage of its online multiplayer and video streaming abilities. The minimum required speeds for basic connectivity to Xbox LIVE include a 256 Kilobytes-per-second download speed and a 64Kbps upload speed. While the 256Kbps connection will allow you to connect to Xbox LIVE, Microsoft recommends a minimum of 4 Megabits-per-second download speed to make the best use of the Xbox LIVE service.
Testing your Internet Connection Speed
You can test your connection speed with Speed Test, an online service that measures your actual Internet upload and download speeds. Log on to speedtest.net and click on the "Begin Test" button to launch the test. During the test you will see the geographic area that you live in represented on a map during the test. Speed Test will send information to a geographically-close server and measure your upload and download speeds in Mbps.
Wired versus Wireless
Microsoft suggests that you connect your Xbox directly to your modem or router through the use of a wired ethernet connection to utilize the most stable connection possible and avoid drops in service. Internet connection speeds can decrease by 35 percent when using a wireless versus a wired connection, according to a 2011 study published by Epitiro.
Other Issues Impacting Performance
While a high-speed broadband Internet connection will provide the best connection possible to Xbox LIVE, there can be other issues impacting performance besides the Mbps rating of your Internet connection. The time of day that you connect to Xbox LIVE can be a factor. Microsoft reports that they have the heaviest traffic during the evening, so connecting during the day may provide a faster connection than during the evening. Microsoft also suggests that you check your current bandwidth when trying to connect to Xbox LIVE. Turn off any downloads or video-streaming services to minimize the bandwidth-usage through your Internet connection.