The hidden bit rate override menu (or secret screen) is where the advanced settings are. You reach it by pressing [HOME] 5 times, [REW] 3 times, [FF] 2 times in fairly rapid succession. It may take one or two tries before you get the timing right. If you accidentally switch [FF] and [REW] in the sequence, it will take you into another menu with software update options that are disabled and have no impact on the player.
In the bit rate override menu, the first item listed is "automatic". This is the default setting and refers to automatic stream selection. The player measures your available bandwidth and uses an algorithm to select the appropriate stream based on the result.
After "automatic" there are several bit rates listed in the form "#.# Mbps". This is how you force a stream. By setting a bit rate, you are forcing the player to forgo the bandwidth test and select the stream closest to the bitrate you designated. If you force the player to select a stream that requires a connection faster than the one between your player and the Netflix server, you will be subject to periodic interruptions during playback when the player empties the buffer and waits for it to be refilled.
The last option in the menu is "enable playback debugging". Enabling playback debugging shows the bitrate of the stream that will play and the results of your bandwidth test when you first start playback. The debugging screen looks like this:
If you force a stream the playback debugging screen will not show, even when you have debugging enabled.
Keep in mind that the bandwidth reported by the box is not the bandwidth of your internet connection, although that is a factor. It is the bandwidth of the connection between your player and the Netflix server.