A thank you for all the info here in the form of more info that you may not know......

Using cheap Sabrent USB audio (lists as CB109  Generic USB Audio device)  out only... 

44.1khz/ 22m /64  

Fooling around w/ shepard tone patch and 1 ADC from arduino (firmata) gives me about 

60-70% CPU load w/ GUI running no SSH.  Will try the same w/ behringer interface when it shows up.

hoping to get audio in working.  

Coolest thing: Just popped in a Model B sd card w/ everything installed. It booted no problem, and just worked.

maybe just a bit faster...

Regular audio out still stinks..... 

Anyone know if GEM will ever work on a Pi?

 Best -Stefan Prosky