I seem to lose performance on my BFL Single with 1.3.1beta (around 70Mhps). Can't say about the CPU usage jumps to much to say (current version and beta)
Some other BFL users are getting the same speed with 1.3.1beta as they do with 1.3.0. Can you check this again? Is it constant at 70 Mhps lower than with v1.3.0?
Tested it again. And i lose 70+ Mhps.