Introduction

We would like to thank Seasonic for supplying the review sample.

Seasonic recently revamped their high-end X series with the addition of several Platinum models on which the Corsair AX760 and AX860 units we have reviewed a while ago are based. They also enhanced all Gold X series members with the new KM3 platform, which carries many changes over its KM2 predecessor.

The X-660/760/860 and the fanless SS-520FL unit are, at the time of this review, 80 Plus Platinum certified, but all other X series models still carry the 80 Plus Gold badge. Today, we will fully evaluate the X-750 PSU which, thanks to its fresh design/platform, promises even better performance than its predecessor that was already a top performer.

The key features of the new X-750 include a fully modular design, the patented modular PCB which integrates the DC-DC converters that generate the minor rails, the hybrid silent fan control system that provides the ability for semi-fanless operation at lower loads/ambient, and its high-quality Japanese caps. Performance wise, the X-750 promises ±1% voltage regulation on all major rails, very low ripple, and a single +12V rail capable of delivering the full power of the unit, which is really convenient since today’s systems heavily utilize this rail. As you can see, all other features are, with the exception of the efficiency certification, identical to the ones of the Platinum X series units; however, the Gold X units cost less, which grants them a very high price/performance ratio. Finally, we admit that we expect a lot from our X-750 test sample today, especially considering the top performance all Seasonic products we have reviewed so far achieved.

Specifications

Efficiency is Gold, and, thankfully, Seasonic equipped the PSU with all available protection features including the rare OTP (Over Temperature Protection) feature. Also, the maximum operating temperature at which the PSU can deliver its full power continuously is 50°C, which is what the ATX specification recommends.

The cooling fan is the usual contender: a San Ace 120 from Sanyo Denki. It is a high-quality fan that uses double-ball bearings for additional longevity. The only downside of this fan is its increased noise output at high rotational speeds.

The unit's dimensions are pretty compact for its capacity, and the provided warranty is extra-long, which is only proper for such a high-end product. Finally, the price looks decent given the features of the unit.


The single +12V rail can deliver the unit's full power by itself, so it is strong enough to support a system equipped with two power hungry VGAs. The minor rails have enough capacity for their duties and 5VSB can deliver up to 3 A maximum current output, which will suffice in most cases.

Cables & Connectors, Power Distribution

Contrary to the Corsair AX760, which is based on the same platform and can deliver almost the same power level, the X-750 is missing two PCIe connectors, which leaves it with four such connectors. Nevertheless, it utilizes the same modular PCB as the aforementioned PSU, so you can easily expand its PCIe connectors if you purchase additional cables. The number of the available SATA and peripheral connectors is also great for the capacity of the PSU.

The length of all cables is satisfactory and will suffice, even in a large chassis. Our only objection here is the short distance amongst the PCIe connectors. They should ideally be 2-5 cm longer. Finally, all connectors use 18AWG wires, which is the standard, and all cables except the one holding the 24-pin ATX connector are flat.

Since this PSU features a single +12V rail, we do not have anything to comment on about its power distribution.

Packaging

The packaging of the X-750 features a plain design with no fancy graphics, nor any vivid colors. A dark background dominates the front with the Gold efficiency badge and the capacity description occupying the top, right corner. A little below them is a photo of the unit's front side and right next to it resides the series description. The overall design of the box exudes a general air of seriousness.


There is nothing of interest on this side. The opposite side holds the unit's specifications table and a description of available connectors. Seasonic unfortunately only mentions lengths of ATX and EPS cables. They should also include length for PCIe and peripheral cables.


On the right, top corner of this side, we find Nvidia's SLI-ready badge, which isn't important; it simply occupies a spot on most PSU packages. The ErP Lot 6 2013 compliance logo is the real deal. Seasonic apparently doesn't account for old ErP Lot 6 2010 compliance and is eager to mention that their units are compliant with the newer and stricter directive.


On the rear side, we find a lot of useful information about the PSU and its features. Seasonic briefly analyses key aspects of their platform on the back: the patented modular panel that incorporates both VRMs (Voltage Regulation Modules) for the generation of the minor rails, gold-plated, high-current terminals that reduce energy losses, highly reliable 105°C electrolytic caps used in this platform, the existence of polymer ones, etc.

They also mention the hybrid circuit for fan-speed control since it allows for fanless operation at lower loads where noise output reaches the lowest possible level, and there is also a graph showing the fan's speed in both normal and hybrid mode. Finally, Seasonic provides some information on the fan the unit is equipped with. Their favorite San Ace fan may not be so silent at high speed, but it is, without a doubt, of high quality.