Seasonic X-Series 850W Power Supply Review

1. Introduction2. Seasonic X-Series 850W (Bundle & Cables)3. Seasonic X-Series 850W (External)4. Seasonic X-Series 850W (Internal)5. Seasonic X-Series 850W (Super High Res Gallery)6. Testing Methodology7. Closing Thoughts8. View All Pages

Recently we analysed the Seasonic X-Series 1250W power supply aimed at the ultra high end enthusiast market. Today we supplement that review with a look at the more cost efficient X-Series 850W model, priced around the £150 mark. This is a fully modular design which has achieved 80 Plus Gold Certification.

Seasonic are using high grade 105c Japanese capacitors with a focus on maintaining low noise levels regardless of the load situation.

In a similar fashion to the 1250W version, the X-Series 850W adopts a “Hybrid Silent Fan Control” design, which offers three distinct operation modes, fanless mode, silent mode, and cooling mode. The X automatically adjusts fan mode and speed according to the ambient temperature level. This brand new design not only optimizes heat dissipation, but also prolongs lifespan of the system by reducing unnecessary fan rotation.

Special Features –

• 80PLUS® Gold Certified Super High Efficiency
• Full Modular Cabling Design
• Patented DC Connector Module with Integrated VRM [Voltage Regulator Module]
• DC to DC Converter Design
• Seasonic Hybrid Silent Fan Control
• Sanyo Denki San Ace Silent Fan
• Conductive Polymer Aluminum Solid Capacitors
• Highly Reliable 105℃ Japanese Brand Capacitors
• Tight Voltage Regulation [±3%]
• Active Power Factor Correction [99% PF Typical]
• High +12V Output
• High Current Gold Plated Terminals
• Dual Sided PCB Layout
• Ultra Ventilation [Honeycomb Structure]
• Multi-GPU Technologies Supported
• All-in-One DC Cabling Design
• Easy Swap Connector
• Universal AC Input [Full Range]
• 5 Years Warranty

The X-Series 850W box artwork is identical to the 1250W version we tested a couple of weeks ago.

The bundle includes a dual pouch storage bag for the modular cables, a regional specific power cable, cable ties, case badge and user manual.

The modular bag is a glossy gold and black design which houses the raft of modular cables, shown above. This can be reused and sealed, to store cables which you aren’t using. The quality of the cabling is first class, they are all sleeved. There are four 6/8 pin PCI-E power connectors to support SLI and Crossfire configurations.

The Seasonic X-Series 850W supply is a plain design with a black finish and stickers on the sides of the chassis. The paint work is deep and it will fit into a variety of systems without problem.

The 120mm fan is hidden behind a black grill. We will take a closer look at this later in the review.

One side of the power supply is fully vented to improve air flow. At the side is a power switch and connector.

The X-Series 850W has several rows of ports for the modular connectors. These are all clearly labelled to avoid confusion. There is a sticker bottom which indicates that the fan will only spin when a certain temperature threshold is met.

Seasonic X-Series 850W Power Supply
DC Output	+3.3V	+5V	+12V	-12V	+5Vsb
Max Output	25A	25A	70A	0.5A	3A
Total Power	125W		840W	6W	15W
	850W

70A can be delivered to the +12V rail, plenty of power on tap for demanding gaming systems.

Seasonic are using a very high grade 120mm Sanyo Denki San Ace fan (9S1212F404). This fan uses dual ball bearings to enhance life span and reliability. It is constructed around 7 blades which are sculpted to reduce noise while maintaining a high level of airflow.

This supply uses only a couple of heatsinks, however with the 80 Plus Gold Efficiency rating and the large fan overhead it should be fine.

Seasonic are not skimping on the component grade in this supply. They are using high quality Japanese capacitors throughout, with the primary design using two Nippon Chemi Con caps, rated 420v 390 uF @ 105c.

The design of this unit replaces traditional wired connections with direct pin to port connections. This reduces the heat generated by the wiring which has the subsequent benefit of reducing lost power, ensuring improved voltage. The unit includes Total Power Protection (OPP), Over Voltage Protection (OVP), Over Current Protection (OCP), Short Circuit Protection (SCP), and Over Temperature Protection (OTP).

On this page we present some super high resolution images of the product taken with the 24.5MP Nikon D3X camera and 24-70mm ED lens. These will take much longer to open due to the dimensions, especially on slower connections. If you use these pictures on another site or publication, please credit Kitguru.net as the owner/source.

Additional technical assistance: Peter McFarland and Jeremy Price.

Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.

We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
100W	1.56	3.35	1.77	5.04	6.65	12.08	0.50	5.06	0.20	-12.00
225W	3.73	3.34	3.85	5.02	15.58	12.05	1.00	5.04	0.20	-12.04
450W	7.52	3.33	8.34	5.00	30.77	12.02	1.50	5.03	0.30	-12.08
675W	11.31	3.31	12.33	4.99	47.47	12.00	2.00	5.00	0.50	-12.09
850W	1.50	3.30	1.16	4.98	63.51	11.99	0.50	4.99	0.20	-12.11

No concerns with the load regulation, holding well across all output stages.

Seasonic X-Series 850W	Maximum Load
	1,033W

We managed to get the PSU to achieve 1,033W before it would shut down, delivering around 183W more than rated specifications! We could almost say this is a 1,000Watt power supply in disguise.

Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.

Cross Load Testing	+3.3V		+5V		+12V		-12V		+5VSB
	A	V	A	V	A	V	A	V	A	V
760W	1.0	3.35	1.0	5.04	60.0	12.00	0.2	-12.02	0.50	5.02
165W	15.0	3.31	18.0	4.98	2.0	12.08	0.2	-12.03	0.50	5.01

The Seasonic X-Series 850w exhibited no problems when dealing with our intensive Cross Loading test. It was tasked with 60A on the +12V rail and it held at 12.00V. The other rails delivered good results also.

We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.

ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.

ATX12V Ver 2.2 Noise/Ripple Tolerance
Output	Ripple (mV p-p)
+3.3V	50
+5V	50
+12V1	120
+12V2	120
-12V	120
+5VSB	50

Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the unit complied with the ATX standard.

AC Ripple (mV p-p)
DC Load	+3.3V	+5V	+12V	5VSB
100W	5	5	15	5
225W	5	10	15	10
450W	10	10	20	10
675W	15	10	25	15
850W	15	15	30	15

Noise suppression results are very good, peaking at 30mV on the +12V rail when under full load. The other rails fall between 5mV and 15mV across the full range of loads. Well within industry tolerance specifications.

Efficiency (%)
100W	84.13
225W	87.87
450W	91.88
675W	90.82
850W	88.35

Efficiency is excellent, peaking at almost 92% at 50% load. Efficiency falls down to just over 88% at full load.

We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.

Today to test the power supply we have taken it into our acoustics room environment and have set our Digital Sound Level Noise Decibel Meter Style 2 one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.

As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.

KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refrigerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum

Noise (dBA)
100W	<28.0
225W	<28.0
450W	29.3
675W	31.7
850W	33.8

The fan activity is temperature controlled, disabling if a certain threshold is maintained. Therefore a portion of the fan activity will be related directly to the ambient room temperature.

In our room we found that loads under 500W translated to an almost silent experience. The fan spins up when the load gets higher and subsequently ambient temperatures increase accordingly. Over 700W and the fan would be audible in a quiet room, although likely drowned out inside an enthusiast system configuration.

Temperature (c)
	Intake	Exhaust
100W	37	40
225W	38	43
450W	42	49
675W	45	54
850W	47	59

As we mentioned earlier there are very few heatsinks inside the Seasonic power supply, so the efficiency and fan performance is important. The temperatures are controlled well however, rising to a maximum 12c above ambient threshold at full load.

Maximum load	Efficiency
1,033 watts	83.77

At 1033 watts, the efficiency level measures 83.77%. Not a practical situation to be running 24/7, but worth noting.

The Seasonic X-Series 850W power supply is just as impressive as the 1250W model which we reviewed a couple of weeks ago. That said, an 850W Power supply makes a lot more sense for a much wider audience, especially as this unit can handle an extended load of 1,000 watts. Not often have we tested an 850W power supply that can sustain a 1,000W load.

Aesthetically we like the appearance of the X-Series 850W. The black paint is deep and difficult to scratch, although it does attract finger prints fairly easily.

The plain black appearance will suit a broad range of systems and we prefer the subdued black fan grill, compared against the bright gold version on the 1250W model.

Technically there are no weaknesses with this design. It delivers high levels of efficiency while maintaining strong noise suppression. The +12V output peaks at 30mV under full load and +3.3V/+5V peak at 15 mV under the same conditions.

The high grade Sanyo Denki San Ace fan is generally inactive below 450W, kicking in harder in the last 200W of total rated output.

The modular design is excellent and Seasonic supply a plethora of high grade sleeved cables which are long enough to be compatible with a tower design chassis.

I was slightly disappointed that the power supply has only 4 PCI E 6/8 pin connectors and cables. With the high level of power output and strong regulation, we feel another two cables could have been added without forcing a reliance on adapters.

We have no hesitations recommending this power supply, it is available from ARIA for £150 inc vat. An ideal choice for an ultra high end enthusiast gaming system.

Pros:

• Excellent build quality.
• Modular design.
• quiet, quality fan.
• efficient.
• stable load regulation.
• can deliver over 1,000Watts!

Cons:

• expensive.
• only 4 PCI E connectors.

Kitguru says: Another winning design from Seasonic.

Become a Patron!