MSI P55-GD85 Motherboard

Voltage Regulator

MSI P55-GD85 comes with a high-end voltage regulator circuit called DrMOS, with a total of ten phases, eight for the CPU (Vcore) and two for the integrated memory controller (VTT rail).

Each phase doesn’t use discrete MOSFET transistors, but integrated circuits containing these transistors. Each “DrMOS” chip (Renesas R2J20602) features three MOSFETs inside (“high side,” “low side” and the driver) switching at 1 MHz, instead of the 250 kHz of traditional voltage regulators, in order to increase efficiency (i.e., less energy is wasted, causing the CPU and memory to pull less energy from the power supply compared to other designs). According to MSI one “DrMOS” phase is more efficient than four traditional phases because of that design.

This motherboard comes with a passive heatsink using a heatpipe on top of the “DrMOS” chips.

All capacitors used on the voltage regulator circuit and on the rest of the motherboard are solid and all chokes are ferrite models, which are better than iron chokes.

Please read our Everything You Need to Know About the Motherboard Voltage Regulator tutorial for more information.

Figure 7: Voltage regulator circuit with the heatsink.

Figure 8: Voltage regulator circuit without the heatsink.

Besides having a high-end voltage regulator circuit, P55-GD85 can disable phases from the voltage regulator circuit as needed in order to save energy, feature called APS (Active Phase Switching). A group of LED’s near the memory sockets indicate how many phases are active at any given moment. MSI P55-GD80 has as advantage over GD85 having a display that indicates the number of active phases.

See how this motherboard uses an EPS12V connector for the CPU.