"It leverages the high performance of low voltage DrMOS devices and multiphase buck control", drmos is driver and mosfet. Like mentioned (by a sibling comment)

"It leverages the high performance of low voltage DrMOS devices and multiphase buck control", drmos is driver and mosfet. Like mentioned (by a sibling comment), it's not a single conversion, but the efficiency is not the prime issue regardless - it's the reaction time and the voltage sag. Load insertion causes the voltage at the CPU (inside) to drop and be significantly lower than the one measure at at the VRM, due to losses at such high currents. The lack of voltage simply causes the systems to crash.