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- Date:
- Friday , September 25, 2009
- Author:
- Paul Johnson
- Editor:
- Kyle Bennett
- Google +1
Seasonic X Series: X-750 Power Supply Review
Fully modular, 750 watts of computing power, high efficiency, and a great build quality has been done before in the world of PSUs, but never quite like this. Seasonic's X Series is an evolution in the world of power supplies.
Build Quality
As we already know the Seasonic X-750 features a single 120mm fan design that has come to be the preferred standard for quiet cooling environments, which Seasonic has been the longtime leader in, due to the ability to move a larger volume of air at slower speeds than a smaller diameter fan. While great for quiet computing environments the key criteria in our evaluation is whether or not the cooling solution is sufficient, not necessary it’s sound level or form factor.
External Build Quality
Externally the Seasonic X-750 is trimmed in basic black with the same style slightly textured black finish that we have come to expect from Seasonic built units. This unit however, is trimmed out with some gold accents and the "Go for Gold!" logo on the side. The rear of the unit has the Seasonic logo once more (though in gold trim this time) and the on/off switch but no voltage selector switch as this unit is full range. The front of the unit houses the modular interface with a little map that locates which connector goes to which point on the unit. Lastly, the top of the unit is dominated by the lone 120mm fan charged with cooling the unit and a small gold Seasonic accent piece.
The Seasonic X Series 750W itself comes in at ~6 1/4 inches. The modular cables provide a serviceable length of ~15 to 22 inches to the first or only connector depending on the cable type selected. Moving on, the sheathing on the cables is generally well done which is good to see.
Internal Build Quality
Once we open the X-750 we are left with one question. Who stole the PSU? The housing is almost empty compared to what we are used to seeing from traditional designs or even from units that feature DC-DC VRM's for the minor outputs. Indeed, this unit only has one main heatsink with three other smaller heatsinks in an odd arrangement (two of which are on the "secondary" side on the main PCB). The fan charged with cooling this unusual arrangement is a Sanyo Denki ball bearing PWM fan rated at 0.13A at 12v. Lastly before moving on, when we flip the main PCB over see some of the cleanest soldering we have ever seen.
Moving over to what I am going to call the primary side for a lack of better phrasing we see first the majority of the input filtering housed on the main PCB (with the remainder on the AC input receptacle). To the left of the first image we first see the pair of bridge rectifiers stuck to a small heatsink followed by the APFC coil to the left of that. In the second image we see the primary capacitors which are a pair of Nippon Chemi-con capacitors rated at 400v 390uF 105c. Lastly, we see attached to the only traditional style heatsink the majority of the power components for this unit which is unusual to say the least.
Over on the "secondary" side we see just about a full complement of solid capacitors provided by Nippon Chemi-con as well as the two heatsinks attached to the main PCB. Interestingly, we see here that the modular PCB is split into two parts. The upper part houses all of the connectors that require the minor rails voltages, 5v and 3.3v, including the Molex, SATA, and the portion of the motherboard connector with 3.3v/5v leads. This is fed by a few 12v leads and grounds. The bottom half of the modular interface PCB houses only components that use 12v and ground leads and it is fed by straight metal connections from the main PCB. This approach is certainly interesting and according to Seasonic more efficient. When we flip the top modular PCB around we see the DC-DC VRM is indeed housed here on the top portion of the modular interface and provides those minor rails output voltages from the back of this PCB right where they need to be delivered.
Build Quality Summary
The overall build quality of the Seasonic X-750 is excellent across the board. At no time does this unit show any signs of corners being cut or compromises being made. The exterior of the unit is well trimmed out with a flat slightly textured rugged black finish and the accents are all subtle for those of you with windowed cases. The cables and modular interface look and feel well constructed with a nice map indicating what connector goes where. The interior of the unit is certainly unique but overall the design and integration looks solid. The PCBs certainly have some of the best soldering we have seen to date! The connections to the modular interface are also a first and according to Seasonic help with efficiency. If nothing else, the ditching of all the wire leads will obstruct less airflow and allow this unit to be more efficiently cooled by the lone overhead fan that is controlled by Seasonic’s special fan controller. The component selection is top notch with the primary capacitors being provided by Nippon Chemi-con as well as the solid capacitors over on the secondary side. Overall, this is an unusual design, but it looks really solid and if it performs as advertised who cares what it looks like!