what is the max transfer speed of the beaglebone black?

What is the max speed the sd bus can handle on the BeagleBone Black? The raspberry pi can do about 20 MB/s…

http://raspberrypi.stackexchange.com/questions/12191/what-speed-of-sd-card-is-better

Can the BBB do better? Can anyone post some benchmarks? I’m mostly consider the BBB because I see that it has EMMC storage which I’m guessing make the OS run faster. I’m using the microSD for storage so I’d like to get an idea of how fast the transfer speed are. Thanks.