Few things have influenced product politics as much as 80 Plus Gold. Seasonic was the first manufacturer to list power supplies on its homepage meeting the EPRI (Electrical Power Research Institute) guidelines, and they presented their first certified models at CeBIT 2009. With the recently launched X-series, Seasonic aims to prove the marketability of 80 Plus Gold PSUs. We have the 750W model for review today, so let's see how it measures up. Is it a great new PSU, or is 80 Plus Gold simply a new way to increase prices?

Beyond the remarkable efficiency and high-quality technology, the power supply contains a fully modular cable system and makes a good impression with its simple elegance. The X-Series also includes "hybrid silent fan control", which regulates the three speed settings of the fan. The power supply runs completely silent up to 20% load, at which point the fan begins to rotate slowly; at higher loads fan speed increases again to enable sufficient cooling. Seasonic uses a PWM fan to allow graceful ramping up of fan speeds, which we will cover later in this review. Beyond the various certifications and features, this ATX 2.3 power supply offers a 5-year manufacturer warranty and uses active PFC to allow its use on all the major power grid standards.

Enermax delivered good results in our previous test with the latest Pro87+/Modu87+ series, and it will likely be Seasonic's main competition. Of particular note is that the noise levels of the Pro87+ and Modu87+ are extremely quiet throughout the load range. Enermax also delivers products catering to the midrange 500W market, but we will have to wait until summer for Seasonic's answer. When the other models are ready, Seasonic let us know that they will have PSUs rated below 500W for those that don't run a high-power system. We should also see additional manufacturers soon with their own 80 Plus Gold offerings, so it remains to be seen who will have the best product. Apart from the marketing hype, we'll need to see new features in order to surpass the competition.

The X-Series has an MSRP of $200 for the 750W unit we're reviewing, but you can find it online starting at $180. So let's see if this expensive power supply is worth the money and if Seasonic can achieve new efficiency levels. We will also look at the construction, voltage output, and the unusual topology; high efficiency isn't the only point of interest with the X-Series.

X750 - Product Contents and Overview
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  • cmdrdredd - Wednesday, April 14, 2010 - link

    I use an HX1000 Corsair PSU in my system, I would have bought this unit because it's higher quality but they don't make more than 750watt units in this series. Why not?
  • 529th - Thursday, April 15, 2010 - link

    The 750 should put most machines today in the most efficient part of the efficiency curve.

    With the 650 model you hit the highest efficiency of 92.1% between 269-292; and most systems draw around there when gaming. My i7 920 (stock clocks,) 5870 (stock clocks,) 6g 1333 1.6v, was right between there; and I'm glad I chose the 650w model. Even then if you are doing a little overclocking, you stay within the 90 percentile between 134w - 588w which is solid. So given the 750w model you can assume another 100w added to the 588w and you'll still be in the 90 percentile which is darn good!

    Of course, not all machines are running stock clocks.
  • 529th - Wednesday, April 14, 2010 - link

    JonnyGuru did a great review on the[rul=http://www.jonnyguru.com/modules.php?name=NDReview...]Seasonic X-650[/url]. The ripple suppression on these things are top notch. Check out page 3.

    Isn't he still a mod here?
  • MamiyaOtaru - Thursday, April 15, 2010 - link

    Got the 750 on ebay for 148 (with shipping) after cashback. Was quite a steal considering the MSRP

    power draw at the wall went from 153 to 123 at idle. Quite the change from my old aerocool zeroDBA.
  • jayce - Thursday, April 15, 2010 - link

    Are power supply manufacturer’s going to be moving towards switching topology between lower and higher loads?
    Given the trend in CPU’s/ GPU’s to use power gating and hard disk controllers spinning down disks when idle, are we going to be seeing power supplies which provide high efficiencies in 50w-150w and 400w+ in the case of a 750w power supply.
  • Bitgod - Sunday, April 18, 2010 - link

    I put together a new system using my old HX620 and I was getting squealing from various components. I decided to take a chance and try a new PSU and I knew I wanted one that was more efficient. I'd seen some of the pics of the inside of the X750 and fell in love with it, it's so clean. So I coughed up the money to get one, and luckily it was worth it because all the squealing noises went away. And it's also drawing less power according to the kill-a-watt tester I plugged it into. So, it's pricey, but if you want a good PSU, this is it.
  • Salsoolo - Thursday, June 3, 2010 - link

    thats a fine psu
    90+ all over over, thats amazing
  • jed22281 - Tuesday, June 22, 2010 - link

    I don't suppose any one could offer some thoughts based on my needs outlined in this thread of mine?
    Much appreciated if anyone can!

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