Efficiency and PFC

Even at 75W (10% load) Seasonic delivers 83.43% efficiency. 115VAC reaches 89% maximum efficiency from 20% to 50% load (150W to 375W), while 230VAC delivers slightly better results as expected. Overall the X750 is as good as the Enermax Pro87+ and Modu87+ with only minor differences. If you want to save energy then the choice between Enermax and Seasonic won't generally affect the result. Instead, you'll want to look at pricing and other features.

At low input voltage, PFC starts at over 0.971 and reaches 0.993 under full load. With 230VAC the trend is lower (again as expected), starting at 0.800 at 10% load. This is still okay for the European power grid.

Cooling

Seasonic has a lot of confidence in their design and so the fan doesn't rotate at all until you hit 20% load. Thus, from 0 to 20% (150W) we have a result of 0 dB(A) on the graphs. From 20% to 50% load the X750 remains silent, but once load goes beyond 50% (375W) the fan RPMs increase rapidly. At high loads the result is more noise than the Enermax Pro/Modu97+, with a maximum noise level of over 30 dB(A). The small heatsinks and open design come into play here, as they have to compensate for the lack of surface area by pushing more air through the PSU. You can also hear the ball bearings inside the fan at maximum RPM.

X750 - Voltage Regulation and Quality X750: Potent for the Price
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  • Londeninfo - Wednesday, September 7, 2011 - link

    My pc psu have been causing troubling me from many days. Whenever I touch the CPU i feel the electric shock.I cant figure out the problem!!!!
    <a href="http://www.londeninfo.com/">Londen</a&g...
  • Londeninfo - Wednesday, September 7, 2011 - link

    <a href= "http://www.londeninfo.com" > Londen </a>
  • Earthmonger - Wednesday, April 14, 2010 - link

    Is it okay if I use this review to comment on something I'm getting really tired of seeing in upper class power supplies? It is? Thanks.

    [quote=Martin Kaffei]The cable sleeves are well done and help keep everything looking neat and organized, as does the fully modular cable system.[/quote]

    This. These cables are not well sleeved. Every time I see bare wires on these expensive new units I roll my eyes, and add $40 to the end cost, since I'll have to completely re-sleeve all cables. It's awesome (seriously) that they're going fully modular these days, but for the price premiums, you'd think they would care more about the details.
  • bigboxes - Wednesday, April 14, 2010 - link

    How anal are you? If you must cover the last 1/4 inch of wires where they meet up with the connector why don't you just use some additional shrink tubing?
  • Minion4Hire - Wednesday, April 14, 2010 - link

    Yea, what's the big deal? To my understanding one of the reasons they don't sleeve them to the very ends is to allow greater flexibility and bends in the cable to help make installation easier, which can be especially useful in smaller chassis. The shrink tubing at the end of the sleeve isn't exactly flexible, and would and would "pad" the back of the connectors by several centimeters if they were butting up against it. Better for the cables? Potentially. But I'm willing to bet that the average person would find it to be that much more painful and annoying during installation.
  • Earthmonger - Wednesday, April 14, 2010 - link

    Quite anal, yes. If a wire isn't completely sleeved, it shouldn't be sleeved at all. It just feels half-assed.

    As for the reduction in flexibility, not all heatshrink is rigid. I have some laying around here that is soft and pliant. Nor does it take several centimeters of heatshrink to do the job.

    I do prefer individually sleeved cables though. Wire clusters aren't flexible enough, whereas I can bend a flat double-row of individuals right around a 90 degree without issue.
  • 7Enigma - Wednesday, April 14, 2010 - link

    What a poor comment. The purpose of sleeving is for better air flow and easier access to components. The terminal ends are kept free for better connectivity.

    You can glitter up your case/components all you want to satisfy the anal inner-you, but for the rest of us, I think we find this more than acceptable sleeving.
  • bigboxes - Wednesday, April 14, 2010 - link

    I know what you are talking about. I just find you are a tad unrealistic. If you want bling then maybe you're looking at the wrong mfg. Seasonic is for the enthusiast. It's fairly plain, but well built and engineered. I prefer function over form and I still think it looks good. Of course I don't have a window or lights in my case. I like quiet. I have sleeving mesh and shrink tubing, but the sleeving on this unit (and all Seasonic PSUs) is top notch. I have sleeved up to (and even over) the connector before. I just think you are asking too much from the mfg in this case. Sounds like you are going to redo whatever someone else does because you have certain tastes that only you can live up to. And that's tottally understandable. I'm sure most people think I'm too anal over my builds too. :)
  • HOOfan 1 - Wednesday, April 14, 2010 - link

    If I saw bare wires...I would stay very far away from the PSU...talk about short circuits....

    Luckily, these wires aren't bare, they are covered in plastic isulation.

    Smartass remark out of the way, there is no way to extend the sleave all the way to the end, the wires would have to be individually sleaved, or done like the flexforce cables...individually sleaving them would raise the price exponentially.
  • MrSpadge - Wednesday, April 14, 2010 - link

    What an amazing comment!

    (1) you need to spot the "missing" sleeve at the end of the cables
    (2) you have to recognize it as something you don't like
    (3) you have to seriously consider fixing it for 40$ in case you'd want to buy this PSU

    I'm not sure anyone else on this planet could fulfill all 3 ;)

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