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
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  • vol7ron - Tuesday, April 13, 2010 - link

    Nice Martin, I've been looking at upgrading my PSU (550W ultra) and I only like buying the modular connectors. $200 still seems kind of high, but almost in the reasonable range. I'd like it to be $150 :)

    Another thing I might be shopping around for is a new UPS, have you guys reviewed any of those recently?
  • HOOfan 1 - Wednesday, April 14, 2010 - link

    There is a 650W version. Selling for $160 at newegg now
  • jeffbui - Wednesday, April 14, 2010 - link

    $138 at ewiz/superbiiz for the 650w version. I couldn't be happier with it.
  • vol7ron - Wednesday, April 14, 2010 - link

    I like the plan for the future though, especially with power supplies since they last long.

    My guess was that the next upgrade would be 750W or higher, the real goal was to have an 800W PSU and UPS. My machine probably only currently uses 350W, but I like to have headroom, especially since I keep adding HDs and will probably take advantage of more PCI slots in the future.
  • Souka - Wednesday, April 14, 2010 - link

    HX650 or HX750 (both are modular)

    HX650 is $120 at NewEgg, I have it... quiet and works well. Reviews show it to be 80+ Silver. but Corsair chose to be Bronze as their own testing (under very hot conditions) didn't qualify for Silver... Kudos to Corsair.
  • Souka - Wednesday, April 14, 2010 - link bad. Corsair PSU is Silver...almost Gold.

    One important thing about the HX650 and HX750 PSU is that they're just shy of 90% effecient at a VERY wide range of loading.

    True, the Seasonic unit does do better at PEAK efficiency (if using 220v) by a few %, but if you're actually going to use a 750W PSU at any other load than this, the Corsair will save you $$ upfront and in the long run with lower power bills.

    My $.02
  • HOOfan 1 - Wednesday, April 14, 2010 - link

    HX650 is bronze...nothing more than bronze

    HX750 is silver and was originally awarded Gold by 80plus.
  • Franson - Wednesday, April 14, 2010 - link

    Are you a bot or something? Take your stupid Corsair fanboyism and shove it....!!
  • Souka - Thursday, April 15, 2010 - link

    Wow... nice post...
  • piroroadkill - Thursday, April 15, 2010 - link

    The HX650 IS a Seasonic design, and I think, by looking at it, the HX750 is a Channel Well design. Regardless, Seasonic was also the OEM for the HX520 and HX620. Seasonic make damn fine power supplies.

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