Seasonic Prime 850 W Titanium PSU Review

Seasonic made an impressive entry in the 80 PLUS Titanium category with its Prime series. This line's current flagship, offering 850W capacity, is being reviewed today. Besides high efficiency, it sports quiet operation and top performance.

We already reviewed the Seasonic Prime 650, which impressed us enough to roll out a rare Editor's Choice award. Today we're testing the top member of Seasonic's Titanium Prime family, offering up to 850W of maximum capacity and similar specs as the last model we evaluated. Without a doubt, this company rocked the boat with its high-end Prime series, based on a new platform.

The Prime 850 W Titanium, or SSR-850TD, features compact dimensions and fully modular cabling. In addition to high efficiency and exemplary performance, the PSU also promises quiet operation. There are two fan modes, normal and hybrid, which can be selected through a push-button located on the front panel. As a result of its Titanium-class efficiency, the SSR-850TD doesn't dissipate much waste heat, so there's no reason for an aggressive fan profile or high rotational speed. On top of that, Seasonic finally got over its obsession with 120mm fans and equipped the Prime family with a larger cooler. It is nice to see Seasonic focusing more on quieting down its products; previously, the Snow Silent units were the only ones able to match Super Flower's high-efficiency offerings.

As an aside, we are anticipating the release of new Prime models soon, since this line will consist of more affordable Gold- and Platinum-rated units as well. In addition, we will likely see the Prime platform branded by other companies partnering with Seasonic.


Titanium-class efficiency, a single +12V rail, modular cabling, and a 50°C maximum output rating are all highlights of this design. In addition, the SSR-850TD is covered by a full suite of protection features that includes over-temperature protection.

The cooling fan uses a Fluid Dynamic Bearing, which offers a 70,000-hour lifetime at 40°C. In comparison, high-quality double ball-bearing fans are rated for 50,000 hours and sleeve-bearing ones go up to 30,000 hours. There are some FDB fans with much higher ratings, but their manufacturers don't specify a maximum temperature. Seasonic, on the other hand, is crystal clear on the matter. We appreciate when a manufacturer doesn't hide such important details.

Finally, Seasonic guarantees its workmanship for 10 years. The company is clearly gunning for Corsair and EVGA with its extra-long warranty.

Power Specifications

Max. PowerAmps20207030.3
Total Max. Power (W)850

The single +12V rail can deliver up to 70A of current, which should be plenty for a high-end gaming system with a couple of flagship graphics cards. On the other hand, the minor rails are limited to 100W combined, though that's still enough for any modern PC. The 5VSB rail is stronger than usual with 15W maximum power output.

Cables And Connectors

Modular Cables
DescriptionCable CountConnector Count (Total)Gauge
ATX connector 20+4 pin (610mm)1118AWG
4+4 pin EPS12V (650mm)2218AWG
6+2 pin PCIe (675mm+75mm)3618AWG
SATA (450mm+120mm+120mm+120mm)2818AWG
SATA (350mm+120mm)1218AWG
Four-pin Molex (450mm+120mm+120mm)1318AWG
Four-pin Molex (350mm+120mm)1218AWG
FDD Adapter (+100mm)1122AWG

The provided cables are quite long, so you probably won't have problems with full-tower cases. However, we'd like to see more distance between the SATA and peripheral connectors (at least 15cm). We do appreciate the fact that Seasonic provides a set of short SATA and four-pin Molex cables for use in smaller enclosures. And we also like the FDD adapter, since fixed Berg connectors aren't often used these days and they only serve to make cable management harder. Lastly, the number of provided connectors is ample for this unit's capacity; Seasonic gives us access to six PCIe connectors and a couple of EPS ones at the same time.

Power Distribution

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

MORE: Best Power Supplies
MORE: Power Supplies 101
MORE: How We Test Power Supplies
MORE: Picking The Right Power Supply: What You Should Know
MORE: All Power Supply Content