Seasonic S12G-450 Power Supply Review

1. Introduction2. Seasonic S12G-450 (Bundle & Cables)3. Seasonic S12G-450 (External)4. Seasonic S12G-450 (Internal)5. Seasonic S12G-450 (Super High Res Gallery)6. Testing Methodology & Results7. Closing Thoughts8. View All Pages

Today we are taking a look at the latest power supply from Seasonic, the S12G 450W. This is an 80 Plus Gold Design and utilises high grade Japanese components throughout. We have already reviewed the excellent high end S12G 750W in November 2013 and it walked away with our highest award. The S12G power supplies are designed to target the mass market enthusiast audience and Seasonic back up the units with a substantial 5 year warranty. It may only cost £55, but how does the 450W version perform?

Seasonic told us that ‘The S12G Series is the newest addition to Seasonic’s families of retail products. The S12G Series is designed to support Intel’s Haswell processors, features standard all in one cabling with more SATA cables and is an affordable solution for a wide range of applications.  It meets the demands of users who are looking for reliable 80 PLUS Gold performance for gaming and overall usage.”

Special features



The Seasonic S12G ships in an attractively designed box with an image of the power supply shown bottom right, alongside some specifications and other details. Inside, the power supply is protected between soft foam pieces.

Accessories include, a small multi language user manual, regional specific power cable, mounting screws and some cable ties.

The S12G power supplies are not modular by design. All of the cables are hardwired into the back of the chassis, shown above. Thankfully they are the flat ‘ribbon' style cables …. excepting the 20/24P connector. The flat cables are proving popular among the enthusiast audience, as they are easier to route.

The Seasonic S12G-450W resides at the bottom of the power output range and as such is designed for a single graphics card with 2x 6+2 pin PCI-E connectors. If you want to run a Crossfire or SLi configuration then you need to be looking at the 650W or 750W models. Both 450W and 550W units are equipped with 8 SATA connectors.


The S12G-450, just like the 750, is finished to the high standards we would expect from Seasonic. It wouldn't be classed as the most stylish looking power supply, but it will suit almost any system due to the plain black appearance. All of the cables are hardwired into the chassis, lowering the cost to the consumer.

The unit passed our ‘screwdriver test'. We run the head of a Philip's screwdriver down the side of the chassis with weak to modest pressure. After all, how often have you accidentally hit a power supply with some tools during a system test phase?

A large 120mm is hidden behind a plain black cooling grill. There is no company branding in the middle of the fan, like many of the most recent Seasonic power supplies we have reviewed.

All of the cables are hardwired into the chassis, as shown above.

One side of the S12G-450 is vented to aid with the cooling process. Next to this is a Seasonic sticker, power switch and cable connector.

The S12G-450 can deliver 37Amps on the +12V output for 444W of the total power output.

Seasonic are using a 7 blade, 120mm JAMICON Dual Ball Bearing Brushless Fan, 12V 0.35A (Model KF1225B1HR-R) in the S12G-450 power supply. These are reasonably high quality fans.


The build quality is excellent and the overall design is very similar to the G Series units we have tested in the past. Obviously there is no modular PCB on one side of the chassis. Soldering quality on the main PCB is also at a very high standard.

The non modular cables run into the chassis and are tied down in several places to protect them against fraying.

Filtering starts with an X cap, four Y caps and a coil. On the main board is a TVS diode, two Y caps, an X cap and two coils.

The daughtercard above holds the PWM controller, which is an Infineon ICE2Hs01G.

Seasonic are using high grade Japanese capacitors throughout the primary and secondary stages. All capacitors are rated 105c.
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
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• 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
	A	V	A	V	A	V	A	V
75W	1.02	3.34	1.45	5.03	4.88	12.11	0.50	5.01
150W	2.43	3.33	3.15	5.03	9.72	12.10	1.00	5.02
250W	3.64	3.33	5.18	5.02	16.53	12.07	1.50	5.01
350W	4.93	3.33	7.08	5.00	23.51	12.03	2.00	5.01
450W	6.77	3.32	9.16	5.00	32.76	12.00	2.50	5.01

Load regulation is excellent and all output maintain close to reference results.

Seasonic S12G-450	Maximum Load
	533.2

We managed to push the supply to 533.2 watts before it would shut down safely.

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
386W	2.0	3.33	2.0	5.03	30.0	12.01	0.2	-12.10	0.50	5.01
171W	18.0	3.30	12.0	5.00	4.0	12.10	0.2	-12.08	0.50	5.00

Our first test placed a heavy load (30a) on the +12 V output with a light load on the remaining voltages. The power supply had no problems dealing with the load changes.

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	10	10
150W	10	10	15	10
250W	10	10	20	15
350W	10	15	25	15
450W	15	15	30	15

Fantastic results and all well within the rated tolerance levels. The +12V output peaked at 30mV at full load, which is another excellent result.

Efficiency (%)
75W	86.71
150W	88.22
250W	92.18
350W	90.01
450W	88.88

The Seasonic S12G 450W is a very efficient unit, peaking at around 92% at 50% load. This drops to around 89% 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 SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) 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 Refridgerator
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
250W	30.4
350W	33.2
450W	34.6

The large fan spins slowly under 300 watts load, spinning up at around 350W and greater. At 450W load however it is audible, but never intrusive.

Temperature (c)
	Intake	Exhaust
75W	35	40
150W	36	43
250W	39	49
350W	42	55
450W	45	57

The supply holds a good temperature variable – rising to a 12c peak at full load.

Maximum load	Efficiency
533.2W	88.13

Pushing the PSU above its rated limits generates an efficiency level of around 88%. This is not a viable ‘real world’ situation, but its interesting nonetheless.
As we said a couple of months ago, the latest Seasonic S12G range of power supplies are designed to target the mainstream enthusiast audience.

Seasonic are trying hard to keep the pricing down, while not compromising on the component selection inside. The retail price of the S12G-450 is around the £55 inc vat mark. Being able to buy a quality unit from Seasonic at less than £60 is certainly welcomed.

Many people think that they need a 750W or greater power supply. Even in 2014, we see a lot of people buying the highest wattage power supply they can find, rather than placing a focus on the quality of the unit itself. This really is a big mistake. Trust us when we say that an Intel or AMD system built around an R9 270X doesn't need a 1250 watt power supply. Even if you want to buy another later, for Crossfire.

Unless you are using multiple high level graphics cards in Crossfire or Sli (or a dual GPU card such as the AMD HD7990) then a quality 450W is often more than enough. Several of our Core i5 and Core i7 overclocked systems, featuring a R9 280X/GTX770 or similar, will often demand between 300-350 watts under gaming load.

Technically we have no concerns with the S12G-450 power supply. It is rock solid and delivered around 530 watts before safely shutting down. Seasonic are known to over specify their power supplies, which offers additional reassurance.

Load regulation is also noteworthy, and the fan never emits enough noise to become intrusive. Ripple suppression is also excellent, falling well within the industry rated guidelines. Seasonic use high grade 105C capacitors in both primary and secondary stages, ideal for long term reliability, especially in warm environments.

The only major downside to the S12G range of power supplies is that they are non modular. Modular cabling adds cost however, so it makes sense for Seasonic to hard wire the cabling as they work hard to reduce consumer pricing.  Thankfully Seasonic have adopted flat ribbon cables, although if you are working inside a space restricted case with poor routing capabilities then you may want to look at one of their more expensive modular designs.

If you are building a new system and want a rock solid power supply without spending a fortune, then the Seasonic S12G-450 deserves serious consideration. At only £55 inc vat, it really is going to prove difficult to beat.

Discuss on our Facebook page, over HERE.

Pros:

• competitive price point.
• built with 105c capacitors both on primary and secondary stages.
• 80 Plus Gold
• delivered 530 watts+
• quiet
• excellent ripple suppression.

Cons:

• Not modular.

Kitguru says: If you are happy routing additional cables then the S12G-450 is a fantastic power supply, built to a competitive price point.

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