400-450W PSU Roundup

Comparison

With the four power supplies tested today, we can get a basic idea about the products in the market. Unfortunately, this is a market where higher quality power supplies are getting rare since 500W is the lower end for most companies. A few good manufacturers make 400W and maybe sometimes 350W models, but with many graphics cards "requiring" 500W and higher power supplies marketing has definitely moved to less reasonable units. Rather than creating a good quality 350W power supply, most manufacturers are more interested in attaching a few more cables, adding a couple more components, and selling a 500W (or higher) power supply.

Seasonic is one of the few companies that continue to cater to this market, so it's not too surprising that in addition to their own brand they are also the production facility for the Earthwatts and Corsair power supplies. Staying with Seasonic, however, the M12II series will come out soon and Seasonic wants to start the series at 500W -- just as they did with the first M12 series. That leaves Maxpoint as one of the only remaining companies looking to continue producing lower wattage models.

Despite the marketing hype, many users really have no need for anything beyond a moderate 400W power supply, and perhaps not even that. Consider our results from the GeForce 8800 GT article: with an upper-midrange system, we still topped out at a whopping 327W -- and that's power draw from the wall, not power supply output! Assuming 80% efficiency for the power supply, that particular test system is only using around 260W of power.

As we have seen today, of course, simply going out and grabbing any old 400W power supply might not be a good idea for such a system. While three of the tested power supplies today perform well, we would be very concerned with the prospect of using something like the Ultra 400W. As usual, you get what you pay for. Unfortunately, it seems as though most of the quality power supplies in this range will disappear over the coming year or two, leaving the lower wattage market to cheaper designs that really underperform.

Before we wrap up, let's take a quick look at how the power supplies stack up in a few meaningful areas. We'll start with fan speeds and acoustics.



Corsair clearly has the lowest fan speeds in comparison to the other units. It stays below 1000 RPM until a load of more than 350W is applied. In most actual computers, it will be nearly silent. The other units start to ramp up fan speeds much earlier, which should be not necessary. Corsair keeps the lead even under higher ambient temperatures, despite the fact that the other three power supply fans are spinning 50% faster. Fan speed doesn't really count for noise levels or fan size, however, so let's look at noise measurements.



Comparing the acoustics is interesting because the Antec shows its potential here. The fan turns slightly faster but still produces less noise. Both the Antec and Corsair have a very low noise level and are practically silent. If you're interested in a low wattage, low noise level PSU, Antec and Corsair are definitely worth a look (as well as Seasonic, naturally). The other two power supplies don't do nearly as well. Thermaltake is even louder than the Ultra unit is, even though the fan spins at lower RPMs. Thermaltake should definitely think about changing the fan -- or maybe redesigning the fan grill, heatsinks, or whatever else is necessary -- to bring performance up to the level of Seasonic, et al.