Hands on: Save power and save money

Modern PCs may feature a number of power-saving technologies and increasingly efficient parts, but a typical system could still easily consume well over 200W running at full steam, or more than 150W even when idle ­ and that doesn’t include the display.

Since most work computers are powered up for at least one-third of every day, their power consumption can represent a significant portion of your electricity bill. This, of course, can seriously add up if you’re running over longer periods of time or operating multiple PCs. The heat generated by PCs also means more work for air conditioning systems, which in turn results in bigger bills.

PCs that consume less power and generate lower heat are of course the answer, but there’s no need for us to abandon high-performance desktops and switch to environmentally friendly laptops.

By switching one component in your desktop PC, you could potentially save power and generate less heat and noise without any compromise in performance. That component is your power supply, and I’ll show you how spending £66 saved me over 10 per cent in direct power consumption, while also generating less heat and noise.

I’ve got the power
At its most basic, a PC power supply simply takes mains AC and converts it into a number of DC outputs to power various components in your PC. In Hands on: Choose the right power supply we detailed each of those outputs and why the total number of watts quoted by a power supply may not give a fair overall indication of how well it will perform in practice.

Just briefly here, a poor power supply could naughtily give the impression of a healthy number of total watts by delivering more amps to the easier but less important +3.3 and +5V ‘rails’ than it does to the harder but critical +12V rail. Second, even once you’ve found a power supply that is realistic about its outputs, it’s important to comfortably over-specify the unit in order to consume the least electricity and generate minimal heat and noise. But how comfortable should that over-specification be?

If a typical PC consumes around 200W under a hefty load, then it would seem reasonable to couple it with something like a 250W power supply. That would give you enough power under load, with a little spare.