Do PCs really have to make noise? Well, if you select a "super silent" power supply ...

       

Obviously not a FAQ, but just taken as Gospel: PC power supply units need fresh air – the more, the better. This has been right from the very beginning when a PC used only around 40 W. There are and have been other power electronic devices around with a much higher input or throughput rating, respectively, but which do without any fans at all. Now, is it necessary for PC power units to be so poorly designed that they have excessive losses, or is it just a culture – a newfangled fashion – that a PC needs to have as many fans as possible to show off its performance?

Initially, during the stone-age of PC technology, the fan (only one in those days) was simply there, with a steady connection to the 12 V DC output of the PSU. Then came the habit of assessing a PC's performance by the number of fans built in, which we are only just overcoming now.

A “silent” PC is now in the in thing, but how silent is a “silent” PC?

This PSU is equipped with a fashionable “large fan”, which can indeed create the same air flow at a lower speed, but is only less noisy if it does actually rev lower.

Also, today’s PSUs claim to have a temperature dependent speed control. For instance, this “super silent” model advertises a “Super Quiet Thermostatic Fan”, which, strangely enough, starts spinning immediately, and not too slowly at all, even when you have assembled the PC in the cellar and the starting temperature of the whole assembly is below 18°C.

The overall success was overwhelming. Indeed, the PC was now less noisy than a vacuum cleaner! How high must the power loss in a PC PSU be if such a lot of cooling is required? This one alleges to have a “High Efficiency”, whatever that means. If the efficiency is as high as the noise is low…

Let us see what can be done about it. Let us first combat the noise and then go a step further and cut out the need for cooling altogether!