Seasonic is a traditional OEM manufacturer, being the real manufacturer behind units from brands like Antec, Corsair and Arctic Cooling (not all power supplies from these brands are manufactured by Seasonic, though). They also sell power supplies using their own brand and today we are going to review their M12D 750 W unit (also known as SS-750EM), which uses a modular cabling system and high-end components. Let’s see whether this is a good unit or not.

One annoying thing about Seasonic is that they have three websites,, and, but retail products like the reviewed power supply can only be found on the later. In our opinion this makes no sense and only makes it difficult to consumers to find out more about their products.

Seasonic M12D 750 W power supplyFigure 1: Seasonic M12D 750 W power supply.

Seasonic M12D 750 W power supplyFigure 2: Seasonic M12D 750 W power supply.

M12D 750 W isn’t a long power supply, being 6 1/2” (16.5 cm) deep, using a 120 mm fan on its bottom and featuring active PFC, of course. It comes with a half modular cabling system, as some peripheral cables come from inside the power supply: two auxiliary video card power cables with one six/eight pin connector each and one SATA power cable, with three SATA connectors, besides the main motherboard cable (which uses a 20/24-pin connector), an ATX12V cable and an EPS12V cable. All these cables have a nylon protection that comes from inside the unit.

The modular system has six connectors and this power supply comes with nine cables:

  • Two cables with one six/eight-pin auxiliary video card power connector each.
  • Two cables with three SATA power connectors each.
  • One cable with two SATA power connectors.
  • Two cables with three standard peripheral power connectors each.
  • One cable with two standard peripheral power connectors.
  • One adapter for converting one standard peripheral power connector into two floppy disk drive power connectors.

All cables are relatively long, with 20 1/2” (52 cm) between the power supply housing and the first connector on the cable. On the cables with more than one connector, there is 5 29/32” (15 cm) between the connectors.

Peripheral and SATA power cables use 18 AWG wires and the main motherboard cable and video card auxiliary power cables use thicker 16 AWG wires, which is great to see.

Seasonic M12D 750 W power supplyFigure 3: Cables.

The number of cables is terrific for the high-end user, however if you want to install more than two very high-end video cards you will need to use adapters, since each very high-end card takes two auxiliary power connectors each and this power supply comes with “only” four of them.

Now let’s take an in-depth look inside this power supply.

Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.