Published: March 21, 2009 | Source: Seasonic | Author: James Napier

Seasonic M12D 750w ATX PSU

Cables & Internal Layout

‘Hybrid modular’ is the name of the game on the M12D with the bare minimum cables required to get your PC up and running being already hard-wired into the unit. This has the advantage of providing some of the most important cables (ATX/EPS/PCI-E) with a direct connection to the PSU’s power while also removing the potential for any dodgy modular connectors to add resistance to the circuit. It does however come at the cost of the PSU not being fully customisable by the user.

In the case of the 750w model Seasonic have hard wired 1x ATX, 1x EPS12v, 1x P4-12v, 2x PCI-E and 3x SATA connectors to the unit. Both the ATX 24-Pin and PCI-E 8-Pin connectors can be reduced down to 20-Pin and 6-Pin connectors respectively to support a wide range of motherboards and graphics cards, whereas the EPS12v 8-Pin connector is not interchangeable and for this reason Seasonic have included a separate 4-Pin P4-12v connector for older motherboards.

A total of 8 modular cables are included, which is plenty for a modular system that can only support up to six cables being plugged in at any one time. Of course two of these connectors are dedicated to PCI-E only, which means that…yes, unlike the OCZ Fatal1ty 700w I reviewed last week…the M12D can support high-end dual graphics card configurations.

Moving on to the more juicy stuff, removing the lid of the M12D reveals a reasonably tidy internal layout with two massive aluminium heatsinks running in parallel along the length of the unit. Hidden beneath the heatsink at the lower part of the picture (below-left) are several inductor coils that perform the PSU’s PFC and AC transient filtering. The heatsink towards the top of the picture also hides some goodies; namely the +3.3/5.0v voltage regulation module and the huge bunch of cables that enter the unit.

Two transformers take centre stage in the unit with the larger of the two responsible for the +12v rail, and the smaller being soley responsible for the 5vsb (standby voltage) rail. Over to the right of these are two large capacitors manufactured by Japanese company Nipon-Chemicon. The transformers carry specification markings of 400v / 390uF / 105c which shows that Seasonic haven’t skimped on quality.

The Sanyo Denki San Ace 120mm fan carries a model number of 9S1212H403, and despite details being pretty thin on the ground when I did a search of google, it appears to be capable of pushing 83CFM at