as i mentioned earlier - the shutdown under load with higher clocks/volts is the ocp protection on the pwm controler.
i have a pretty good idea how to up the limit but lack the tools to do it. we need to alter the values of 4 surface mount resistors and pencil jsut sint going to cut it as we need the final resistances to be as near as possible exactly the same.

OFC we need to be aware of the warning given above, but i have quiet confidence given that the 4 phase system on my old abit AX8 survived 3200mhz/1.75V on my old X2 without any heatsinking and we used to have many a board running 2 phase on 70w thunderbirds - so it should be technically possible.

ill dig up the spec sheets for the FETS if anyone is interested.
also, fyi, the PWM temp is read from a thermistor positioned right next to the FETS where you would expect to see the LPT port usually, tiny black surface mount component sitting just out from under the heatsink in a big island on the pcb. (i traced it back to the winbond monitor chip in the bottom right corner, close to the C1 led.)