Hands on: The Pico power supply put to the test

The words PC and power supply conjure up images of a hefty box screwed into the back of a case, but as the rise of small form factor systems has proved, PC power supplies don’t have to occupy a large volume.

Indeed, as you reduce the power requirements of a PC it’s amazing what you can get away with.We're testing the PicoPSU, which at just 31 x 45 x 20mm is officially the world’s smallest snap-in DC-DC ATX power supply – to put that in perspective, it’s about the size of two AA batteries next to each other.

The power supply components are built into the ATX connector itself, allowing the entire unit to be plugged directly into a motherboard.

A cable harness offers two full-size drive power plugs and one floppy drive plug, while a second lead is used to connect to an external 12v laptop-style AC power adapter.

Since there are no fans, the power supply runs silently, and it’s clearly ideal for systems where space is at a premium. That said, it could, in theory, snap into any system, replacing a standard power supply unit.

So the big question then is what kind of specification is it capable of powering?

The designers of the PicoPSU claim the unit is theoretically capable of delivering up to 120w of power, although this depends on the kind of external adapter it is connected to; we tested our PicoPSU with a 110w model. The next step is figuring out what 110w can power in practice.

Counting the watts
The PicoPSU is best suited to low power consumption boards such as Via’s Epia range, and I had it powering one plus a 3.5in hard disk and laptop-style slimline optical drive without a problem.

Where it starts to get interesting, though, is with more traditional desktop components.

It’s not wise to blindly connect a PicoPSU to an existing system and keep your fingers crossed that it’ll boot up.

To be safe you should spend some time measuring the power consumed by your PC during a variety of tasks with its existing power supply, and only swap it for the PicoPSU if it consistently and comfortably comes in below the maximum draw.

To do this you’ll need a power meter such as a Maplin model which costs £24.99(product code L61AQ).

By connecting an appliance to the meter, then connecting the whole thing to a mains socket, you can measure exactly how much power it’s consuming.