If you use over 1.3V for the GPU (which certainly isn´t recommended), do yourself a favor and DO NOT run Furmark.
The VRM can provide around 360A of current without burning, and a GPU running at >1.3V might just exceed it in Furmark (depending on leakage). The higher your "ASIC Quality" (GPU-Z) is the higher your leakage level is and vice versa. Higher leakage means the GPU will require less voltage to operate, however it´s maximum safe voltage level is lower at the same time. Lower leakage parts require higher voltages, however their break down voltage is slightly greater too.
Note that the VRM current capability is completely temperature dependant, so don´t expect it to survive at high temperatures.
It can provide 360A at 25°C, but it can still burn with <150A load at 110°C.
High ASIC "Quality" (Leakage) = Lower operating voltage, larger current draw, hotter, less energy efficient (due higher losses)
Low ASIC "Quality" = Higher operating voltage, lower current draw, cooler, more energy efficient
Unless you are using LN2 you definitely want the leakage to be as low as possible.
Even under LN2 the high leakage characteristics are only desired because the difference in voltage scaling.
All ASICs despite the leakage have some sort of design specific absolute voltage limit. The low leakage ASIC might run into this limit prior reaching the maximum clocks.
You can use this software the check the default, leakage dependant voltage of your CPU specimen: http://1drv.ms/1Hln01F
The software must be run at default settings
(as it came from the factory; clocks, voltages), otherwise the results will be invalid.
Unless your default voltage is greater than 1.250V you should never exceed 1.300V.
Also never trust the VDDC voltage reading displayed GPU-Z or Afterburner.
Even at stock the voltage reads around 56mV too low and the discrepancy only increases with the increased current draw (higher clocks and voltage).