I use my Cubietruck as a Samba server. Some day I noticed the transfer rate when copying files from my Mac with OS X El Captian was only around 10 MB/s. As the Cubietruck has a gigabit ethernet port the transfer rate should be much higher. I also remembered the transfer rate to be around 30 MB/s in the past. Not as fast as gigabit can deliver but I guess CPU load is a factor here.