Cougar STX 550w Non-Modular Power Supply Review

Ripple

Ripple testing determines how consistently the voltage supply is being delivered to where it needs to go. In brief, you are looking for lower figures and none too dramatic charts. So, let’s get this out of the way because on the surface the charts and figures don’t look too good, at least, not unless you really understand them.

Similar to our prior testing, while the Cougar STX performs well up to average load, beyond that, things start to get a little wilder. By the time we get to 100% load, we start to see some big results in the 3 voltage channels. The biggest of which is clearly the 12v ripple. Is this something to be worried about though? The short answer is yes and no. The figures are certainly higher than we are accustomed to seeing, but at the same time, we’re more accustomed to power suppliers which cost at least twice what the Cougar STX does. Even so, all the results are well within the specified EU regulations.

At 100% load, 12V ripple must be under 100 and within 50 for 3.3v and 5v respectively. This meets that and as such falls entirely in line with specifications. Given how important the 12V rail is though, I would have liked to see this figure a lot lower and the spikes a little more compact.