Introduction

While we've reviewed many higher-end (and higher-cost) power supplies, we've neglected the lower power segment. We hope to address that omission with today's roundup of four units ranging from 400W to 450W. Not many manufacturers these days make units rated at less than 500W - especially if we're talking about high-quality power supplies. Seasonic - both on their own and as an OEM manufacturer - is one of the few companies that continue to supply this market segment. We recently tested Seasonic's 330W and 500W models and found they were more than capable of powering most decent systems. There are far more midrange and lower systems on the market than high-end systems, so we thought it prudent to look at several competing models from other companies.


The type of components used in a computer determines the power requirements for the system. If you want to build an extreme performance, highly overclocked computer then you will need a large (and high-quality) power supply. On the other hand, if you're mostly going to be doing office work, most of the "best" power supplies are complete overkill. In fact, even most higher-end systems rarely require more than 500W of power. So why do we have these 1000W+ PSUs? In a word: profit. Assuming you're not going to be running multiple graphics cards or a significant number of hard drives, one of the power supplies we're looking at today -- or something similar to them -- should be ideal.

Because of the potential for greater profits, power supplies with lower ratings are getting rare -- not many manufacturers that want to produce these units anymore. We talked to Silverstone not too long ago about a 300W version of their Element series. The conclusion was that the price for the production is similar to higher-end power supplies and it wouldn't make sense to build these power supplies anymore. That seems surreal when we think about the number of users that don't need more than 500W, but it appears that the minimum price for a quality power supply -- regardless of wattage -- has bottomed out at around $65. That's not to say you can't find cheaper power supplies out there, but the quality of such units is at best... suspect, as we will see shortly.


As usual, we are testing with our Chroma programmable loads to load each rail to a specific amount. This is important to get truly accurate results and not merely approximate values. We conduct tests in two different temperature environments. One is normal room temperature of 25-26°C, while the second environment goes from room temperature and increases steadily up to 50°C. Especially during the higher temperatures we will see how good the power supplies are and what whether or not they're truly worth your hard-won clams. Components inside will perform much worse at higher temperatures, but we expect any good quality PSU to deal with such test conditions without failing.

On the DC output graphics, we show the range of highest and lowest voltage. There is usually a bit of variance, particularly with multiple 12V rails, but with a PSU roundup we want to convey as much information as possible without simply bombarding our readers with graphs and charts. In essence, we will show the voltage range on each rail at various load points. This is especially easier to read and understand when you have multiple 12V rails since we will show them all in one graph together.

Note: If you would like to know more about our testing methodology, equipment, and environment, please read our PSU testing overview.

Antec Earthwatts 430W
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  • zeroidea - Wednesday, November 07, 2007 - link

    The Antec PS featured in this article is currently on sale at staples.com for $30.

    http://www.staples.com/webapp/wcs/stores/servlet/S...">Link
    Reply
  • SilthDraeth - Wednesday, November 07, 2007 - link

    I know it falls outside of the 450Watt max, but it is still below the 500 watt barrier. I just bought the psu for a midrange system I built my mom, I know it works well, but I don't have the ability to test everything.

    One can wish right?
    Reply
  • Noya - Tuesday, November 06, 2007 - link

    If you look around (buy.com), the Corsair 450vx can be had from $51-61 pretty regularly, and at that price it's untouchable. I must say I've had one for about two months and haven't had any problems with it. Reply
  • smthmlk - Tuesday, November 06, 2007 - link

    Can we have a full list of caps in each unit? Noting the primaries is nice, but what about the others? Thanks. Reply
  • Talcite - Tuesday, November 06, 2007 - link

    Thanks for finally putting up O-scope readings, it's quite nice to see them. One thing I'm concerned about though is the lack of explication or analysis.

    For example, is the entire o-scope range 200mV in the 12v readings or is it one division? Also, there's a number of strange spikes in all the o-scope readings. I'm pretty familiar with the 450VX o-scope readings (mostly from other sites) and I haven't noticed any spikes of that nature in their readings. It probably isn't, but is the equipment faulty?

    Thanks for putting the readings up anyways though, they're a nice addition.
    Reply
  • Super Nade - Tuesday, November 06, 2007 - link

    Those strange spikes are probe noise. If the probe is coupled incorrectly, you will see this artifact. This cold be due to any number of factors like EMI for instance. Following the ATX guideline on using 0.1 uF output coupling caps will minimize this to a great extent. Reply
  • MrOblivious - Tuesday, November 06, 2007 - link

    You have to look at the sampling time on the readings to compare between sites. Different sampling times will make the traces appear a bit different. Reply
  • phaxmohdem - Tuesday, November 06, 2007 - link

    I just recently built a rig for a buddy using a Thermaltake PurePower (or ToughPower.. can't remember) 480W Unit and it works like a champ powering a Core2 Quad Q6600 CPU, 2GB RAM, 2HDD's, two Optical Drives, 8600GT, TV Tuner and a few fans. (Wish I knew about the Corsair PSU when I spec'd that system out).

    But yeah, Unfortunately most people equate Watts to overall quality.... not unlike the MHz war of days gone by. Power supplies are one of the hardest components to convince people to spend extra on for some reason. FFS, electricity is kind of the basis of the whole dam computer!

    Eventually it ends up as "Oh well. Go ahead and get that 600W $30 power supply and let me know how that goes for ya. I could use a good laugh, and don't say I didn't warn you."
    Reply
  • strikeback03 - Tuesday, November 06, 2007 - link

    Maybe Anandtech should go ahead and list the weight of each PSU. That has long been used as an estimate of quality. Reply
  • jonnyGURU - Tuesday, November 06, 2007 - link

    Not any more. Topologies have changed to the point where you can have very light quality units and very heavy crap. Weight is NOT a factor. Reply

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