My experience on a November Jupiter with 305 is so far that it works for one board, avg is >700 and temperature is 80+
Enermax 1500W PSU seems not to be sufficient as it is shutting off when I overclock all 4 boards and cgminer starts putting work on them.
I'm running stable at 2B5 and 2C5 with max temperature up to 80 °C and reaching with this ~830GH/s
I'm using "spi-test -s 50000" not the 55000 Mhz value, btw.
I'll leave it for good now and keep watching
You're running at 80C without any failing VRM's? When I overclocked a Nov Jupiter a few VRM's started failing after temps passed 65C. I'm going to try again when I have time to take the cases off and point an external fan on them since it ran fine for about 15 minutes at lower temp...