Seasonic FOCUS PLUS Platinum 850W PSU Review

850 watt computer power supplies from Seasonic are nothing new to us, but Seasonic is taking a bit of a different direction with this Focus line of PSUs. The Focus Plus Platinum has been designed with a small footprint in mind, specifically built for those looking to build high powered small form factor computers like HTPCs.

continued...

Build Quality

As we already know the FOCUS PLUS Platinum 850W features a single 120mm fan design like many other offerings on the market that has come to be the preferred standard for quiet cooling environments 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

Article Image Article Image Article Image

Article Image Article Image

The exterior of the FOCUS PLUS Platinum 850W is just like what we have seen from previous FOCUS PLUS units. That said, since today's unit is a FOCUS PLUS Platinum power supply, we have an unit that is trimmed out in silver/platinum. Other than difference in accent color, the FOCUS PLUS series of units are just about identical. The quality of the exterior seems to be excellent, once more, while the layout of the unit is typical of what we see with single overhead fan designs that have modular cables and APFC. When we look at the finishing touches, we again see the new fan guard design that features a straight wire grill, the FOCUS+ branding, embossed sides, and labeled modular interface. The underlying finish is a textured black finish that seems to be very high quality. All in all, the FOCUS PLUS Platinum 850W looks very sharp and well done like all of the previous FOCUS PLUS units we have seen.

Article Image Article Image

The FOCUS PLUS Platinum 850W comes in at a total length of ~5 1/2 inches while the cables come in at a length of ~19" to 27" to the first or only connector. Additionally, the cables are all sleeved in black mesh, which is very close to being complete, or are the FlexForce style cables are completely sleeved (obviously), or are a combination of the two. Additionally, at the heat shrink on certain cables you will see a small bulge. This bulge is due to the addition of Nippon Chemi-con solid capacitors in these cables.

Internal Build Quality

Article Image Article Image Article Image

Article Image

Once we open the top of the FOCUS PLUS Platinum 850W, we see the same platform that we have seen on all of the previous FOCUS PLUS units we have reviewed. Starting with the fan, we see a Hong Hua FDB fan rated at 0.45A at 12v. Paired with this fan we once more see at least 5 heatsinks of various sizes. Also once more, the topology used in this unit is a full bridge LLC primary and a secondary where we have synchronous rectification with DC-DC VRMs for the minor rails. When we look at the back of PCB, we see the 12v MOSFETs and soldering that is very neat once more. Seasonic has done an excellent job with this aspect of the unit's build quality on each example we have seen so far and today is no exception.

Article Image Article Image Article Image

Article Image Article Image

Moving on to the primary side, the FOCUS PLUS Platinum 850W's input filtering begins up on the housing itself with a PCB that has some X and Y capacitors attached to it as has been the case on the previous FOCUS PLUS units. The input filtering then trails onto the main PCB where we find that it is complete. The bridge rectifiers are found next sandwiching a small aluminum heatsink and this time they have a better alignment than what we saw with the 550W model in this line recently. As we move around to the primary side proper, we find a coil along with the APFC power components on a heatsink. Behind this heatsink we find the main input capacitor which is provided by Nippon Chemi-con. This capacitor is rated at 400v 650uF 105C. Next to, or around I should say, this capacitor we see a pair of transformers and then, towards the center of the PCB, the switching transistors attached to heatsinks.

Article Image Article Image Article Image

Article Image

As we move over to the "secondary side," we see three heatsinks for the secondary power components arranged around the large transformer in the center. Scattered throughout this area is a mix of solid and standard electrolytics from Nippon Chemi-con. Up against the modular PCB, we see another add-in PCB which houses the DC-DC VRMs once more and populating this PCB are a smattering of Nippon Chemi-con solid capacitors. When we move over to look at the modular PCB itself, we see that the single layer PCB is generally cleanly constructed. On the front side of the modular PCB, we see a number of solid and standard capacitors that are once more provided by Nippon Chemi-con.

Build Quality Summary

The FOCUS PLUS Platinum 850W is yet another example of the excellent FOCUS PLUS line of power supplies from Seasonic. Of course, that means that not much has changed today from what we have seen with previous FOCUS PLUS units as they all share the same platform. Beyond sharing the same platform, the finish, modular cables, layout, branding, etc are all basically the same as previous FOCUS PLUS units as well. So, the exterior of the unit features a fit and finish that seems to be very high quality for its product segment once more. When we move to the interior build quality on this unit we see excellent execution and very good attention to detail. The component selection is again high quality as we see a Hong Hua FDB fan along with capacitors from Nippon Chemi-con (solid and standard). All in all, today's FOCUS PLUS Platinum 850W is very much like what we have seen before and, once more, it is a bit nicer than we would expect for the intended market segment. Now that we have seen all of that, again, let's move on now to the load tests and see how this unit does there.