I was just thinking about the maximum speed of either Mochad or HG running on Raspi and wondering if this has to do with either the Raspi or the USB drivers being used. If it's drivers slowing things down, that would require either something integrated into the Linux kernel itself probably. But, if it's Raspi, could overclocking help? I've seen people running XBMC et. al. running up to 1GHz pretty regularly with only additional cooling fins. Would a higher clock rate increase the USB performance though? I really have no experience with how the clock speed affects bus transfer rate so this is a serious question.
Also, I'll try running this test on a Windows 7 machine to see if the speed is the same. If so, then the Raspi itself shouldn't be the limitation.