The contents of the package are what you'd expect. You get the required four screws and power cord, naturally, along with a Seasonic sticker, a user manual with product data and safety references, and a cable bag for storage of the modular cables. The power supply is well protected by packaging and comes in its own bag.

Seasonic prefers a large single-rail 12V design, rated at 62A (744W). As we've seen in other recent power supplies, the reason for the high rating of the 12V rail, which nearly corresponds to the total rated output, lies with the DC-to-DC conversion. All the smaller rails come off the +12V rail. The small rails are rated at 25A each with a combined output of 125W; that's comparatively weak compared to some older PSUs, but since modern PCs usually don't need much from the low voltage rails, this will hardly be a problem.


Seasonic likes to keep their power supplies very simple and eschews any fancy aesthetics like LED fans or custom paint jobs. The X-series looks elegant and subdued, though there are some aesthetic improvements compared to the old M12D series like the honeycombed holes instead of the classical fan grill. Only a simple X-Series sticker and the modular sockets at the front interrupt the black color. The length of the casing is just 160mm, making the X750 much smaller than comparable products.


As mentioned, Seasonic favors a fan with PWM control. They chose a 120mm Sanyo Denki 9S1212P4M61 with ball bearings and seven fan blades. The blades are rounded off in contrast to many other brands. The power consumption of the fan amounts to only 0.13A and a plastic guard blocks part of the intake area to help direct airflow. We spoke with Seasonic at CeBIT about how important the fan is as it's the only mechanical component in a power supply. When we asked how much the fan costs, sales manager Walter Sun simply answered wide-eyed and laughing, "It's very expensive."

Seasonic X-Series 750W X750 - Connectors and Cable Lengths


View All Comments

  • 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? Reply
  • 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=]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. Reply
  • 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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