Thanks.
I tried running that also. I came to the conclusion that there wasn't enough horsepower on the PI to handle the amount of work the ANTS's were giving it. I moved to an old PC and everything was running well after that. Be interested also if someone else has some tuning tips to tweak the PI? I had also tried putting a faster SD card in the PI but that still didn't seem to increase the throughput.
EDIT: I tried doing this with S1's. I see you are using U1's. The 500mh/s may be due to you not using a Cgminer tuned for U1's? Until I changed to a specific version with the U1 parameters set.
AntMiner U1 device options:
--bmsc-options
--bmsc-freq
--bmsc-rdreg
eg:
--bmsc-options 115200:20
The values are baud : timeout, and timeout is 20 * 100ms
--bmsc-freq 4F02
The value following:
0581 : 150M
0681 : 175M
4F02 : 193M
0781 : 200M
0881 : 225M
0981 : 250M
0A81 : 275M
0B81 : 300M
0C81 : 325M
0D81 : 350M
0E81 : 375M
0F81 : 400M
5081 : 425M
5181 : 450M
5281 : 475M
5381 : 500M