ocaholic - PSUs > Seasonic Prime Gold 850W Review

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Preview

Page 2 - Preview

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Delivery and Specifications

Connector	Connector count	Cable count	Cable
Main Power (24/20 pins)	1	1	610mm
CPU (8/4 pins)	2	2	650mm
PCIe (8/6 pins)	6	3	675mm
SATA	10	2	450mm
SATA	10	1	350mm
Peripheral	5	1	450mm
Peripheral	5	1	350mm
Floppy	1	1	100mm

The delivery of the Prime Gold 850W is very good. Considering the wattage we like that there are three PCIe cables with two connectors. Apart from that up to ten devices with SATA power plug as well as five devices with Molex connectors can be provided with power.

With this power supply Seasonic is offering a single rail design regarding 12V. In total you get 70A, which can be turned into heat by the graphics cards for instance.

Specifications (according to Seasonic)
Voltage	Current	Power
+ 3.3V	20 A	100 W
+ 5V	20 A	100 W
+ 12V	70 A	840 W
- 12V	0.3 A	3.6 W
+ 5Vsb	2.5 A	15 W

80 Plus
Load	10%	20%	50%	100%
80Plus	-	80%	80%	80% / PFC .90
80Plus Bronze	-	82%	85% / PFC .90	82%
80Plus Silver	-	85%	88% / PFC .90	85%
80Plus Gold	-	87%	90% / PFC .90	87%
80Plus Platinum	-	90%	92% / PFC .95	89%
80Plus Titanium	90%	92.5% / PFC .95	94%	90%

Form Factor	ATX 12V
Dimensions	150 mm (W) x 170 mm (L) x 86 mm (H)
Fan information	Fluid Dynamic Bearing
Cable information	Fully modular
Electrical features	Operating temperature	0 - 50°C (derating from 100% to 80 % from 40°C to 50°C)
	MTBF @ 25°C, excl. fan	150'000 hours
	AC Input	Full range
	Protection	OPP, OVP, UVP, OCP, OTP, SCP
Warranty	12 years

Page 3 - Delivery / Specs

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A Look Inside

At a first glance we already see a nicely and well-manufactured enclosure, which is a solid hint towards a high-quality product. Apart from an elegant design the paint job is good looking and well-executed.

The Prime Gold 850W has been equipped with a Hong Hua 135mm fan (model number HA13525H12F-Z) and which can be found also in the Prime Gold 1000W and Prime Platinum 1000W units as well. It's a Fluid Dynamic Bearing fan and it's rated at around 150,000 hours at 25°C.

Right behind the AC receptacle there starts the input filtering stage, where we find one X cap and two Y caps. Going one step further to the main PCB we see four Y caps, one X cap and two large chokes. Furthermore there is a TVS diode, which helps protecting the circuitry from voltage spikes. The PFC section is created with two FET 5R190CE and a single diode.

On the secondary side there is a CM6901 PWM controller, which is clearly visible. All the capacitors come from Nichicon and Nippon Chemi-Con and are therefore of Japanese origin. Furthermore there is a Weltrend WT7525 power supply supervisor chip, which enables all the protective functions such as over voltage detection, under voltage detection, over current detection and quite a few more.

Apart from that the secondary side features a daughter board which has been equipped with all the moduler connectors and it's been soldered to the main PCB allowing Seasonic to minimize efficiency losses. Last but not least soldering is on a very good level, which is what we've come to expect from Seasonic's high-end power supplies.

Page 4 - A Look Inside

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Result Analysis and Discussion

Efficiency
Load	Pin(W)	Pout(W)	Efficiency
10%	97.07	86.01	88.60%
20%	189.65	173.03	91.24%
50%	437.90	435.67	92.93%
100%	994.90	878.63	88.31%

The 80Plus Gold certification requirements (88% - 92% - 88%) are surpassed especially at 20% Load. The full load efficiency is a bit higher at 230V AC. This is the case with most of today's PSUs and it mainly originates from the reason of lower losses in the AC filtering stage and the PFC at 230V AC. The 230V AC 100% load efficiency is 92.93%.

Output Stability
Load	Rail	Loading(A)	Output(V)
10%	3.3V	1.07	3.39
	5V	1.07	5.03
	12V	6.22	12.14

20%	3.3V	2.14	3.39
	5V	2.13	5.02
	12V	12.49	12.19

50%	3.3V	5.36	3.37
	5V	5.32	5.01
	12V	31.16	12.32

100%	3.3V	10.69	3.33
	5V	10.62	4.98
	12V	61.95	12.53

The voltage regulation of this PSU is very good. It makes use of a DC-DC topology. This means, that the Seasonic Prime Gold 850W is mainly a 12V PSU and then generates its 5 and 3.3V from 12V. This is a modern approach, and since the load is mainly on 12V it makes a lot of sense. For almost any PSU which makes use of this topology crossload tests do not present a problem.

Page 5 - Result Analysis and Discussion

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Conclusion

With the Prime Gold 850W, Seasonic released a high-end power supply. There is a costly AC filtering stage and the massive use of Japanese capacitors, which - amongst other parts - add up to a great product. Design wise, we really like the solid enclosure and the black paint.

This unit comes with active cooling and the fan installed looks pretty silent. The Prime Gold 850W is fully-modular and the bundle contains everything you could ask for. The cables are long enough for any ATX case and there is a bunch of accessories included in the delivery, which even helps with cable management. The bundle includes several cables but only few of them come with flat design. We would like to see all flat cables, and not a mixture of flat and sleeved cables.

At the moment the Prime Gold 850W is available on Geizhals for almost 150 Euro with a 12 year warranty plan, which is simply industry leading.

This high-end power supply is absolutely worthy of receiving 4 out of 5 stars. If you want to build a high-end setup or just a gaming PC, we suggest to check out the Seasonic Prime Gold 850W power supply.