Seasonic SS-350M1U Industrial Power Supply

When last we met, I showed you a brand new offering from Seasonic in the form of a very long 1U form factor 500 watt unit. Something else came along for the ride: the SS-350M1U. An even smaller unit, this is a 350 watt model that also features 80 Plus Gold certification. How did Seasonic manage to get a 350 watt power supply into something little bigger than a paperback book? We’re going to find out right now.

REVIEW INFORMATION
SUPPLIED BY: Seasonic
MANUFACTURER: Seasonic
PRODUCT: SS-350M1U 350W
PROD LINK: SS-350M1U Product Page
PRICE: $64.99
Price is at the time of testing!

SS-350M1U 350W Industrial PSU

Your eyes are not deceiving you. I am indeed looking at yet another server based unit today. This time, the terms of engagement include this here Seasonic unit, the SS-350M1U. At 350 watts, it is a fair bit smaller than the one I reviewed last, both physically and in terms of capacity.

Despite this, the unit in question is still certified as 80 Plus Gold.

SS-350M1U 350W Industrial PSU

Initial impressions? Och, et’s tineh!!! Luuk’a thot wee fahn! Ok, ok, I won’t try to type Scottish again. You can put down the haggis. On second thought, just throw the haggis. I like the stuff. Throw that bottle of Scotch too, while you’re at it. Not at my head!!!

Seriously though, this might be one of the smallest units I’ve ever looked at, second to that old Hiper M300. Hope it handles being a power supply better than that one did, let me tell you.

SS-350M1U 350W Industrial PSU

Yes, folks, this here is a modular unit about the size of a large paperback book.

SS-350M1U 350W Industrial PSU

And because it’s about the size of a book, there is no power switch. There’s probably no room in there for one. Looks like we’re dealing with an Adda fan, rather than that Sanyo Denki shrieker we found in the 500W unit.

SS-350M1U 350W Industrial PSU

Like the 500W unit, there are vents in the top.

SS-350M1U 350W Industrial PSU

Also, like the 500W unit, the unit has a fanless mode. Nice. When possible, I enjoy not listening to these little fans run. They tend to have a whiney, screamy approach to doing their job. Insert obligatory Kardashian joke here.

SS-350M1U 350W Industrial PSU

A picture of the two next to each other, for size comparison. The 500W is not only longer, but it is also wider. Both units are 40mm high.

SS-350M1U 350W Industrial PSU

Here’s the label for you. In keeping with the unit’s small size, you get a small output. Although, the 12V rails are surprisingly strong in the combined rating, which indicates there’s probably some VRM action going on for the minor rails.

SS-350M1U 350W – DC Output
DC Output +3.3V +5V +12V1 +12V2 -12V +5VSB
12A 16A 18A 18A 0.3A 2A
Max Power @ 40°C 80W 348W 3.6W 10W
350W

That’s right, folks, this unit is so small that it will not do full rated power up to fifty. Rather, it de-rates starting at forty. So, I’m going to aim for forty in the hot box and see what happens. This unit is not listed in the spec sheet as having overtemp protection, so I don’t really want to go higher than that.

SS-350M1U 350W Industrial PSU

The modular interface. It is fully modular… kind of.

SS-350M1U 350W Industrial PSU

This is why it’s only kind of modular. All you get is one long chain of wires. And yes, the longer connector on the power supply is the same ATX 24 pin connector you’ll find on your motherboard. Fear not, however – the actual ATX connector on the harness will not plug in there. The clip on the connector is too wide to fit the notch on the power supply. So, you can only plug the harness in the right way.

SS-350M1U 350W Industrial PSU

Here’s a demonstration of the right way.

SS-350M1U 350W – Cabling
Type of Cable Length from PSU
Modular Cables
20+4 pin ATX connector 300 mm
4 pin CPU 330 mm
SATA+SATA 280+145 mm
SATA+SATA 280+145 mm
5.25″+5.25″+3.5″ 335+150+150 mm
Unit Dimensions (L x W x H)
190 mm x 81 mm x 40 mm