did a few test and anything with :950 produces asic timeouts
53:2:750   14.4Gh/s
53:2:850   20.25Gh/s HE 1.2%
52:2:850   20.3   HE 1.13%
53:2:750   13.44Gh/s
54:2:850   20.39Gh/s   HE3.9%
55:2:850   13.07Gh/s   HE35%
50:2:950   asic timeout
49:2:950   asic timeout