As suggested i've tried again:
- lowered priority, upped nb voltages 1 notch an run 10 tests: no residual norm variation but system went crazy;
- lowered priority, upped nb voltages 2 notches and 10 run tests: system went crazy and error wents out;
- lowered priority, swapped everything at stock settings an run 10 tests: no residual norm variation but system went crazy;
I think i'll have to wait for newer release of this sweet test tool, as i'm not confident seeing nb and sb temps going throttling around from -64°C and 0°C, lcd poster flashing, and usb wireless dongle going crazy.