When you're assembling a basic system with or without an entry-level card you don't need more than 300-450 watts to power it. These PCs also benefit from a good and stable PSU, but there's a lot of junk available in this lower segment. We thought that was a good reason to separate the wheat from the chaff, so we put 39 power supplies through our standard testing process.
If you build a PC with an Intel Ivy Bridge or AMD A processor and rely on the integrated graphics of those chips, you're going to have to try very hard to get it to use in excess of 150 watts. Just do the math, the processors have a TDP of 65 of 95 watts, the motherboard and RAM no more than 30 watts, maximum 10 watts for a hard disk and few more watts for the case fans. Even with everything going on full power it falls just short fo 150 watts. That means that a PSU of 300 or 350 watts is more than enough for the computer. If you add an entry-level or mid-range graphics card to the equation, the consumption goes up to 200 or 250 watts. Then a 400 or 450-watt PSU is fine.
And in the segment of 300 watts up to 450 watts there is lots of choice, as these are the power supplies that sell the most. It's also the segment with the most poor quality products, such as PSUs that can't deliver the promised capacity, are very inefficient or fall short in other ways. The cheapest one you can buy for 19 euros already, and when you consider this price includes manufacturing costs, packaging, shipment from China and the fact that the manufacturer, distributor and retailer need to make a profit, you know that a lot of corners had to be cut.
Our tests confirm that there is a huge difference in performance and quality in this segment, so if you need a low-wattage PSU it's worth it to do your homework. Or you can let us do the hard work and benefit from the conclusions. A good PSU doesn't have to be expensive, but poor-quality power supplies can't always be recognized by a very low price either. So keep on reading!