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Today we look at the latest release from Seasonic – the Snow Silent 750W power supply. Regular readers may remember we reviewed their higher cost 1050W model back in December last year. This unit is fully modular, has 80 Plus Platinum certification – and incorporates a new low noise fluid dynamic bearing fan.
Seasonic have earned many awards with KitGuru over the years – we like their no nonsense, no compromise attitude. They aim firmly at the enthusiast audience by offering great build quality and by incorporating high grade Japanese capacitors in their designs – even in their lower cost models.
Seasonic back these Snow Silent power supplies up with a full 7 year warranty, always a good thing to see.
Snow Silent Overview:
- 80PLUS® Platinum Certified Super High Efficiency
- DC Connector Panel with Integrated VRM [Voltage Regulator Module]
- DC to DC Converter Design
- Dual Copper Bars
- Active Power Factor Correction [99% PF Typical]
- Conductive Polymer Aluminum Solid Capacitors
- Highly Reliable 105°C Japanese Aluminum Electrolytic Capacitors
- Gold Plated High Current Terminals
- Ultra Tight Voltage Regulation
- High +12V Output
- Dual Sided PCB Layout
- Seasonic Patented Hybrid Silent Fan Control
- Ultra Ventilation [Honeycomb Structure]
- Full Modular Cabling Design
- Multi-GPU Technology Support
- All-in-One DC Cabling Design
- Easy Swap Connector
- Universal AC Input [Full Range]
- 7 Years Warranty
The packaging is very plain – obviously white, to match the design ethic of this unit. There is a small image of the power supply visible in the bottom corner of the box.
Inside the power supply is protected between thick foam panels. The cables are all stored in a cardboard box at one side of the box.
The power supply is wrapped inside a soft, white, felt bag.
Seasonic bundle a user manual, cable ties, and mounting screws. They also include a reference sheet to help with cable connection to graphics cards. Basically if you are using a graphics card which takes more than 225watts under load then use two separate PCIe power cables rather than two headers on a single cable.
The main motherboard power cable is sleeved, however all other cables are the flat ‘ribbon’ style, which proves popular with system builders who have to route a plethora of cables behind a motherboard tray. The quality of all the cables is excellent.
| Cable | Connectors |
| MB 20+4 pin | x1 (610mm) |
| CPU 4+4 pin | x1 (650mm) |
| CPU 8 pin | x1 (650mm) |
| PCI E 8 pin (6 pin +2) | x4 (600mm) |
| SATA | x8 (530mm+150mm+150mm) |
| SATA | x2 (530mm+150mm) |
| MOLEX | x3 (550mm+150mm+150mm) |
| MOLEX | x2 (350mm+150mm) |
The cables are all high grade flat ribbon style to help with the routing phase of the system build. The main MB 20+4 cable is sleeved. There are a total of 10 SATA connectors, meaning this power supply is also ideal for a massive storage server system. Those running an SLi or Crossfire rig will be happy to note a total of four 6+2 pin PCI e connectors. The Snow Silent 1050W model has eight PCI e connectors.
I said it back in December 2014, and my opinion hasn't changed since then – these are attractive looking power supplies. The lettering on the side of the power supply is actually black and silver.
There is a little silver accent (line) running across, and upwards on the side panels. These are stuck onto the side panels. We noted back in our review of the 1050W model that the silver sticker had torn a little. The sticker on the 750W unit was fully intact, which is good to see.
Paint quality is high, and it passed our screwdriver test. This involves running the head of a Philips head driver down the side of the chassis with light to medium force. After all, how many times have you accidentally connected with a power supply during a system build? Even if the power supply did scratch however, it is silver underneath so its actually almost invisible against the white paint – unless you study closely.
The Snow Silent measures 170 mm x 150 mm x 86 mm (LxWxH). The 1050W model is slightly longer – measuring 190mm.
A large white (almost cream) fan is visible behind the grill. We will take a closer look at the fan when we open the housing up later in the review.
The modular panel is laid out with two rows of connectors. The main motherboard connector is situated top left. There is a fan control switch which alternates between ‘hybrid' and ‘normal' modes. The CPU and PCI-E connectors stretch across the bottom row, underneath the peripheral headers.
The other end of the power supply is vented, with a power connector and switch at the side.
Above we can see the specifications of the power supply. Seasonic are classing this one as a ‘XP2S' unit, the 1050W unit was classed as an XP3 model.
| Seasonic Snow Silent 750W (XP2S) |
|||||
|
DC Output
|
+3.3V
|
+5V
|
+12V |
-12V
|
+5Vsb
|
|
Max Output
|
25A
|
25A
|
62A |
0.5A
|
3A
|
| Total Power | 125W | 744W | 6W | 15W | |
| 750W | |||||
This power supply can deliver 62A on the +12V rail. Plenty of power for a powerful SLI and Crossfire configuration. If you need more amps on the +12V rail, then the 1050W model can deliver 87A (with twice as many PCI E power connectors available).
Seasonic have opted for a Ong Hua 120mm fan, Model number HA1225M12F-Z. This is a high grade Fluid Dynamic Bearing (FDB) fan designed for low noise emissions.
These fans not only tend to emit lower noise levels, but they are rated to last longer as well due to the lubrication of the bearing itself.
The Seasonic XP platform design is well built, and the soldering quality is excellent throughout. Not the first time we have tested an XP2/XP3 unit.
Behind the AC receptable is a sealed PCB which is home to some of the components of the EMI filter – a single X cap, four Y caps and a CM choke. The other components of the filtering stage are on the main PCB, which include an MOV, two pairs of Y and X Caps and two more CM chokes.
The primary side is a full bridge design with an LLC converter for lossless switching. The secondary side uses a synchronous design with +12V fets on the main PCB. The DC-DC converters are installed on the modular PCB to help reduce power loss.
The main PCB and modular PCB incorporate high grade Japanese electrolytic and solid capacitors. Seasonic are using two high grade 105c Japanese Nippon Chemi Con capacitors rated 420v 270uF (540uF combined). This is a high spec configuration for a 750 watt power supply – this Antec Edge 750W for instance (a Seasonic S-12G/G Series design) ships with a single Rubycon 420v 470uF capacitor.
On this page we present some high resolution images of the product taken in our professional studio with a Canon 1DX camera. 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 | |
|
75W
|
1.23
|
3.34
|
1.19
|
5.06
|
4.95
|
12.13
|
0.50
|
5.01
|
0.20
|
-12.04
|
|
150W
|
2.17
|
3.34
|
2.83
|
5.06
|
10.07
|
12.12
|
1.00
|
5.01
|
0.30
|
-12.04
|
|
375W
|
6.15
|
3.33
|
6.05
|
5.05
|
26.15
|
12.11
|
1.50
|
5.01
|
0.50
|
-12.05
|
| 565W |
10.31
|
3.33
|
10.86
|
5.03
|
38.34
|
12.08
|
2.00
|
5.00 |
0.60
|
-12.06
|
|
750W
|
10.72
|
3.33
|
13.84
|
5.03
|
53.59
|
12.07
|
3.00
|
4.99
|
0.80
|
-12.06
|
Load regulation is fantastic, holding tight within 1.5%
| Seasonic Snow Silent 750W PSU | Maximum Load |
| 875W |
We managed to reach around 875W before the unit would shut down gracefully, after the protection kicked in.
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 | |
| 734W | 1.0 | 3.32 | 1.0 | 5.05 | 60.0 | 11.97 | 0.2 | -12.03 | 0.50 | 5.01 |
| 154W | 15.0 | 3.32 | 15.0 | 5.00 | 2.0 | 12.10 | 0.2 | -12.02 | 0.50 | 5.00 |
The unit passes our Cross Load testing with a set of excellent results. Even when we hit the +12V output with 60A, the line held at 11.97V.
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 |
| 75W | 5 | 10 | 15 | 5 |
| 150W | 10 | 15 | 15 | 5 |
| 375W | 10 | 15 | 25 | 5 |
| 565W | 10 | 15 | 25 | 10 |
| 750W | 20 | 20 | 40 | 15 |
The +12V output peaked at 40mV at full load which is a good result. +3.3V peaked at 20mW and the +5V output hit 20mV at full load. No issues with the power supplies noise suppression.
|
Efficiency (%)
|
|
|
75W
|
88.56
|
|
150W
|
90.67
|
|
375W
|
94.21
|
|
565W
|
93.45
|
|
750W
|
92.12
|
The power supply delivers great efficiency results, peaking at over 94% at 50% load. This drops to around 92% at full load. Impressive results.
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)
|
|
|
75W
|
<28.0
|
|
150W
|
<28.0
|
|
375W
|
30.3
|
|
565W
|
32.8
|
| 750W | 33.9 |
The fan in the Snow Silent 750W is an exceptional performer, holding at under 34dBa at full load. We would class this power supply as very quiet most of the time – almost inaudible with a general load under 300 watts. The fan can be heard at loads over 500 watt – however the move to a quality fluid dynamic bearing fan has certainly helped.
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
75W
|
36
|
39
|
|
150W
|
38
|
40
|
|
375W
|
39
|
43
|
|
565W
|
45
|
51
|
|
750W
|
47
|
59
|
The high levels of efficiency of this unit help reduce expelled heat. At full load we measured a +12c variable.
|
Maximum load
|
Efficiency
|
|
875W
|
91.5
|
For those interested, we measured efficiency when stressing the unit to breaking point.91.5 percent efficiency at 875W … hardly practical, but interesting regardless.The Seasonic Snow Silent 750W power supply is an eye catching design – clearly targeting the audience who not only demand a high quality power supply, but perhaps have a white Corsair or NZXT case with a window. It will look spectacular in front of white or blue LED lighting.
Technically this unit is very proficient and it doesn't exhibit any alarming issues. We wouldn't expect Seasonic to cut corners and we are glad to say they have not. They have recently started adopting large fluid dynamic bearing fans and this has helped to reduce noise levels a little over their older designs. No one is likely to complain about that.
Our real world testing verified that the supply was able to successfully power a high end gaming system, incorporating a 4790K and two GTX980 graphics cards. It was actually capable of sustaining a 850 watt load for many hours, although if you need this kind of power delivery on a regular basis we would advise opting for the more expensive 1050 watt unit. Ideally you would want to be running between 40-70 percent load to achieve maximum efficiency, and cooler running temperatures. If you can afford it, a 1250Watt unit would even make sense for a sustained 850Watt load.
Many 750 watt power supplies adopt a single capacitor for the primary stage, but Seasonic have opted for two 105c Japanese Nippon Chemi Con capacitors. At 750 watt load this power supply is actually not tasked close to its absolute limit – an intelligent design by Seasonic as this will reduce long term component failures.
Technically we rate the XP2S and XP3 supplies as class leaders. They produce stable levels of power, and are over specified intentionally for their respective classifications. Ripple suppression is excellent, load regulation is stellar, and overall efficiency is extremely high. The pure modular design, super build quality and high grade cabling will appeal to the enthusiast audience who want to be sure they are giving their system quality power.
As we publish today we have no pricing information for the Seasonic Snow Silent 750W power supply but as the 1050W unit is priced around £199.99 inc vat, we would take an educated guess at a price around the £150 inc vat mark. We will update this page with more pricing information as soon as possible.
Discuss on our Facebook page, over HERE.
Pros:
- built to exacting standards.
- quality paint work.
- pure modular design.
- low noise fluid dynamic bearing fan.
- 7 year warranty.
- rock solid.
Cons:
- the white colour won't suit every system build. GunMetal Silver next?
Kitguru says: Another quality design, to slot in below the high end 1050 watt model.
