Review Index:

Seasonic Snow Silent 750W Power Supply Review

Manufacturer: Seasonic

Introduction and Features

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It’s always a happy day at the PC Perspective Test Lab when the delivery truck drops off a new Seasonic power supply for evaluation! Seasonic is a well-known and highly respected OEM that produces some of the best PC power supplies on the market today. In addition to building power supplies for many big-name companies who re-brand the units with their own name, Seasonic also sells a full line of power supplies under the Seasonic name. Their new Snow Silent Series now includes two models, the original 1050W and the new 750W version we have up for review.

The Snow Silent Series power supplies feature a stylish white exterior along with top level Seasonic build quality. The Snow Silent-750 is a next generation XP-Series (XP2S) power supply that comes with fully modular cables and a 120mm cooling fan with Fluid Dynamic Bearings. It features an upgraded S3FC Hybrid Fan Control Circuit that provides fanless operation up to ~50% load. The Snow Silent-750 is designed to provide high efficiency (80 Plus Platinum certified) and tight voltage regulation with minimal AC ripple.

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Seasonic Snow Silent 750W PSU Key Features:

•    High efficiency, 80 Plus Platinum certified
•    Fully Modular Cable design with flat ribbon-style cables
•    Seasonic Patented DC Connector Panel with integrated VRMs
•    Upgraded Hybrid Silent Fan Control (S3FC: Fanless, Silent and Cooling)
•    120mm Fan with Fluid Dynamic Bearings (FDB)
•    Ultra-tight voltage regulation (+2% and -0% +12V rail)
•    Supports multi-GPU technologies (four PCI-E 6+2 p connectors)
•    High reliability 105°C Japanese made electrolytic capacitors
•    Active PFC (0.99 PF typical) with Universal AC input
•    Dual sided PCB layout with dual copper bars
•    Energy Star and ErP Lot 6 2013 compliance
•    7-Year manufacturer's warranty worldwide

Please continue reading our Seasonic Snow Silent-750 power supply review!

PSU Testing Methodology

Establishing an accurate load is critical to testing and evaluating a PC power supply.  PCPerspective’s power supply test bench can place a precise DC load on the PSU under test.  Each power supply is tested under controlled, real-world conditions up to its maximum rated load (at 40ºC), using both 115 VAC and 240 VAC line voltage.  Our current suite of tests includes:

•    DC Load Regulation
•    AC Ripple and Noise
•    Efficiency
•    Differential Temperature
•    Noise

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The Seasonic Snow Silent-750 power supply was evaluated on both features and performance.  A full range of equipment was used to test the power supply under controlled load conditions.  

•    (2) CSI3710A Programmable DC load (+3.3V and +5V outputs)
•    (4) CSI3711A Programmable DC load (+12V)
•    (3) 218W Precision resistor load bank (+12V)
•    Switchable precision resistor load bank (-12V and +5VSB)
•    Agilent 34401A digital multimeter (Accuracy ±0.0035% vDC)
•    Extech 380803 Power Analyzer (Accuracy ±0.5% of full scale)
•    DS1M12 "StingRay" digital oscilloscope (20M S/s with 12 Bit ADC)
•    Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC
•    Extech Model 407738 digital sound level meter (Accuracy ±1.5 dB)

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The following cables/connectors were used to connect the Snow Silent-750 to the PCPerspective power supply test equipment.
•    (1) 20+4 pin ATX
•    (1) 4+4 pin EPS/ATX12V
•    (1) 8 pin EPS12V
•    (4) 6-pin PCI-E
•    (2) SATA
•    (2) Molex

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June 26, 2015 | 02:15 PM - Posted by nevzim (not verified)

The only thing I would like to see is 2-4 fan headers for semi-passive case fans.
Also 15-20% passive operation threshold (X-series) makes more sense then 50% as it is kind of hard to dissipate 375W out of the case without a fan.

June 26, 2015 | 02:50 PM - Posted by Anonymous (not verified)

I'm sure that you're mistaken about the 375 watt dissipation. At 92% efficient, it would be something like 30 watts, before the fan kicks on.

I have had zero issues with any of the Seasonic power supplies that I've purchased and have an older 750 watt model in my main rig. I would definitely consider something like this for a future high-end build.

July 5, 2015 | 10:49 PM - Posted by Anonymous (not verified)

Exactly. The rest of the heat is energy used by the PC though it would be more than 8% heat dissipated by the PSU since it would suck some heat back into the power supply.

That's why it is also based on the temperature.

June 26, 2015 | 03:04 PM - Posted by nevzim (not verified)

I was talking computer case not power supply case. If you deliver 375W to power your computer you need to get rid at least this amount of heat from the computer case.

June 26, 2015 | 03:53 PM - Posted by Samhain (not verified)

Would it be easy to swap the fan out for something like a Noctua? I believe some of their 140mm fans work in 120mm openings.

June 29, 2015 | 08:43 PM - Posted by BlackDove (not verified)

Why would you do that when one of the main reasons is to get the special fan? Does Noctua even make fans or do they just rebrand too?

June 26, 2015 | 06:33 PM - Posted by RickH (not verified)

Very nice, but why is it upside down? Everything is oriented as if the fan is expected to be pointing up, but in almost all cases it will be installed with the fan pointing down. Old cases put the PSU above the CPU with the fan down, and modern cases put the PSU at the bottom with the fan pointing down to pull in outside air from underneath. Why would they be expecting the fan to usually point up?

June 27, 2015 | 03:59 AM - Posted by nevzim (not verified)

Valid question is why there are so few cases where motherboard is turned 90 degrees.

June 27, 2015 | 02:09 PM - Posted by Lee Garbutt

Actually, there might be more people than you think installing the PSU with the fan up (myself included). With a PSU mounted in the bottom of an ATX case with the fan up - it adds to overall case cooling. This can help suck warm case air out of the sometimes stagnant area below the GPU card. The trade-off is causing the PSU to run a little warmer than it would with the fan down (sucking cool, outside air) but good PSUs like the Seasonic, are rated for up to 50 deg C operation. Not for everyone, but a good option for some.

November 11, 2015 | 10:01 PM - Posted by Anonymous (not verified)

The fan is sucking air in, not pushing air out. It's blowing over the internals of the psu. If it was installed on the top of a case it would act as an exhaust. Which would be optimal as heat rises.

June 29, 2015 | 05:08 PM - Posted by ArdWar (not verified)

At page 3, I think that fan curve hysteresis is actually increased. Reducing hysteresis actually increasing the frequency of fan switching on-off when temperature is near equilibrium at setpoint.

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