OCTools - Reinventing the Tools of OC - Seasonic

OCTools - Reinventing the Tools of OC 

Seasonic Super Tornado 400 

Power Supply Unit 

by Ramil Tranquilino 

March 21, 2004 

Overclocking Forum 

Overclock.net 

Latest Review 

Mushkin PC3200 

222 Level II Rev.2 

(L2V2) 1Gb Dual 

Pack 

Manufacturer: Seasonic 

Introduction 

Picking up a power supply unit for your computer is certainly something that 

one has to choose carefully nowadays. It is this very hardware that can 

make or break your high performance system. One can go cheap and of 

course expect below standard quality. One can also go expensive by buying 

well known and proven reliable brands. Some opt for power supplies that 

look liked it was made in Vegas with all those light effects or you can have a 

solid, state of the art, well priced power supply unit with all the latest 

technology but still looks very simple. 

The last one will probably describe the power supply unit that we have on 

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our test bench today. Armed with the latest improvements in PC power 

supply technology, the Seasonic Super Tornado 400 offers what most 

power supply doesn't have in terms of advance electrical features. Let's find 

out why this power supply is different from the others... 

Who is Seasonic? 

I have to admit the Seasonic brand of PSUs sounded a bit new to me. 

Unlike Enermax, Antec, Thermaltake, etc which are probably familiar to 

most, Seasonic's presence here is just starting to get noticed. You would 

think it's because they are new but really, Seasonic has been on the PSU 

business since 1975. In fact, because of their very long experience, they 

have amassed so many certifications and approvals than most company in 

the same business. Certainly a proof of the quality of their products. 

In 2000, they became the first PSU maker to provide PC and IPC market 

cost-effective Active PFC solutions. That year they also designed and 

applied S 2 FC (Smart and Silent Fan Control) towards PC and IPC products. 

These achievements have been the benchmark for current PSU makers 

applying the same technology in their PSUs. 

The brand says so much about their products. And in this respect, I can 

safely say just by knowing the PSU maker, that Seasonic is not some 

cheapo brand that just popped out of nowhere and started producing PSUs. 

Next: The Super Tornado 400 PSU 

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The Super Tornado 400 PSU 

The first thing that will come into mind when you say tornado is lots of 

power and wind and that is probably where it got its name from. Sporting a 

huge 120mm fan and an ultra ventilation design, this PSU will surely keep 

your system cool. 


Overclock.net 

With a slogan of "the advanced choice for gamers and overclockers", it is 

obvious that the target of this power supply is the enthusiast market. 

Whether it will live up to its promise, we will find out soon enough. 

Latest Review 




Pack 

The Super Tornado 400 is equipped with the latest in power supply 

technology. Features like Active PFC, S 2 FC, Forward Converter and 

Universal Free Input are some of the advantages it has over its competition. 

Specs 

The unit complies with the latest Intel ATX/ATX 12V spec which is v1.3. The 

Seasonic Super Tornado 400 is a true 400W PSU that it outputs a 

sustained 400W with a max of 450W. It is also worth noting that total 

combined output of the 3.3 and 5V rails is around 200W (46A) max. Below 

is a picture with the breakdown of each individual rail voltage output 

together with the general specs. 

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Specification complies 

with the latest ATX/ATX 

12V 

Support Intel P4, PIII, 

Cleron, AMD Athlon XP, 

Duron and VIA C3 

4-in-1 Protection (OVP, 

OPP, OTP & SCP) 

MTBF > 100,000 hours @ 

25°C 

Additional connectors: 

+12V for P4, auxiliary 

power & fan monitor 

Power supply size: 5.8" x 

5.5" x 3.4" (150mm x 

140mm x 86mm) 

PFC harmonics 

compliance: EN61000-3-2 

class D 

EMS compliance: 

EN55024 & EN61000-6-2 

EMI/RFI compliance: 

CISPR22, EN55022, 

EN61000-3-3, AS/NZS 

3548 & CFR47 part 15 

class B, EN61000-6-3 

Safety compliance: 

IEC60950, IEC60950-1, 

EN60950-1, UL60950 7 

UL60950-1, GB4943, 

GB9254, GB17625-1 

Layout 

Obviously the first thing that can be noticed of this PSU is that it is very plain 

looking. Some will probably say boring. The casing is made of steel and the 

internals looks dull with its aluminum heatsink and black colored fan. 

Compared to other branded (non Active PFC) PSUs, the Seasonic Super 

Tornado 400 is definitely lighter. That may sound bad coz traditionally more 

weight means better quality but you'll understand later why an Active PFC 

PSU like the Tornado 400 is lighter. 

Even though the fan looks plain, it is huge. The 120mm cyclone cooling fan 

outperforms all dual-fan units by doubling the airflow with half the RPM and 

noise. It is capable of giving out 70CFM of air. Its placement is also strategic 

as it prevents lubricant leakage and produces 0% chafe on the bearing. 

With its S 2 FC (Smart and Silent Fan Control) feature, it reduces noise 

without increasing temperature. Automatic temp adjustment prevents 

manual errors. This feature also extends fan life by eliminating unnecessary 

rotation. What's the difference between Seasonic's S 2 FC and other "noise 



killers"? Seasonic's "Smart & Silent Fan Control" technology is not only 

quieter than other brands, but also cooler. Superior intelligence in the 

thermal fan control circuit provides minimal noise under 90% of operational 

conditions while allowing maximum cooling airflow precisely and only when 

it is needed. 

Complementing the huge fan to create an ultra ventilation chassis design is 

the PSU's honey comb structure that creates maximum ventilation and 

minimum air resistance. This design also enhances airflow to solve thermal 

and noise problems. Making the system quiet and cool at the same time. 

Just what the enthusiast ordered. 

There are more than enough connectors for all your hardware. There are 8 

x 4-pin molex connectors, 2 x floppy connectors, 1 x P4 and 1 x auxiliary 

connector, 1 x ATX connector and 1 fan monitor connector. A single SATA 

power adaptor has been included in the mix. Another one would have made 

it even better. 

A universal free input (100-240V full range) is one of the benefits of having 

Active PFC. This eliminates the risk of frying your PSU in case you move 

into another country where the voltage requirement is different and you 

forgot to switch the voltage adjustment slider on your PSU. 

A cable management kit is included in the package and it is called Dr. 

Cable. There is nothing fancy here. Just your standard looms, cable ties, 

cable mounts and such. Quite good to keep your system tidy, creating 

better air circulation in the process. 



Why Active PFC? 

First of all what is PFC? Short for Power Factor Correction, PFC is the 

relationship between working (active) power and total power consumed 

(apparent power). Simply, power factor is a measurement of how effectively 

electrical power is being used. A higher power factor represents a more 

effective use of electrical power. Normally, PSUs without PFC function has 

a PF of around 50% only. This alone tells you the benefit of PFC like 

reduced electric bills, increased system capacity and improved voltage. This 

all equates to improved stability. 

But why Active PFC? What's wrong with Passive PFC? Here's a cut and 

paste explanation. Passive PFC, using inductor, capacitor circuitry to 

reduce harmonic current, because power source frequency is 50 Hz or 

60Hz low frequency, it needs a large inductor and capacitor. Moreover, the 

power factor improvement is only around 75%~80%. Active PFC, using 

active components (control circuit and power sine conductor On/Off switch), 

the fundamental working theory is to adjust input current wave-form to 

simulate input voltage waveform. With this method, we can achieve power 

factor near or equal to the 100% power factor target. Active type power 

factor correction using active component (control circuit and power sine 

conductor ON/OFF switch). Its fundamental working theory is to adjust input 

current waveform to looks like input voltage waveform, this can reach the 

point where power factor of 1 goal. 

Also, the input voltage range can be 90Vdc to 264V without additional 

switch for choosing the voltage range. To have a universal voltage model, 

this power factor regulator is a very important additional value. Otherwise, 

the cost is increased more. Active PFC improves Power Factor to more than 

95%, which surpasses the 75%PF with Passive PFC solution. Thus Active 

PFC is more energy saving than Passive PFC. Lighter equipment will be the 

trend for all PSU. Passive PFC PSU adopts cumbersome components that 

make it much heavier than an Active PFC PSU. That answers the question 

as to why the Seasonic Super Tornado 400 is surprisingly lighter than most 

branded PSU makes with only Passive PFC. 

Benefits of Active PFC: 

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Large buffer to EN harmonics requirement to ensure compliance. 

Opportunity for future cost decreases as ICs requirement volumes 

increase. 

Low risk in terms of material shortage. 

A more "professional" solution than Passive one. 

Full range feature comes with less cost. 

Perfect power factor approach 1 for power utilization. (Environment 

friendly) 

Better competition when power goes up was the trend of CPU's 

requirement. 



Negatives of Passive PFC: 

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Mass production of inductor must be accurate due to small buffer to 

EN harmonics limit. 

Heavy weight that might create problems during transport. (Vibration 

& shock) 

Possible shortage of ferrite material. 

Vibration noise if structure is not fixed correctly. 

Poor competition (cost and performance) when power up to 300W or 

more. 

Next: Test Setup, Results & Conclusions 

Disclaimer: The pages on this site are designed to help anyone interested in overclocking their PC. They 

contain tools and information useful in setting and monitoring system performance. All products and 

trademarks are the property of their respective owners. Tweak at your own risk, we assume no 

responsibility on damages that may occur from the use of these softwares and informations. 



Test Setup 

Hardware 

Chaintech 9CJS Zenith P4 i875P Canterwood 

Intel P4 2.4C 800mhz SL6WF Malaysia OC'ed to 3.0GHz (250FSB) 

NVIDIA GeForce FX 5950 Ultra 256mb OC'ed 

Enermax 550w PSU, Thermaltake PurePower 480w PSU for comparison 

2 x 80Gb Seagate SATA drives 


Overclock.net 

4 x 80mm Case fans 

2 x Optical Drives 

Corsair Hydrocool200 

Latest Review 




Pack 

Results 

We tested the unit by looking at the voltages given out by the different rails with 

the system at highly overclocked speed. Each rail has an acceptable range of 

voltage output needed to keep the system stable. The closer and more constant 

it is to the desired voltage range, the better. We compared it to readings taken 

from our trusty Enermax 550w PSU and to our recently reviewed Thermaltake 

PurePower 480w PSU to see if it at the same level as the popular and tested 

brands. 

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Seasonic Super Tornado 400W 



Thermaltake 480W PSU and Enermax 550W PSU 

Above results tell us that the Seasonic brand is more reliable in giving voltage 

output on the 12v rails compared to the other 2 PSUs. However, its performance 

on the 3.3v rail is not as superior as the 2 brands. Saying that though, all voltage 

output on the Seasonic PSU falls within the acceptable range. Noise output 

when compared to the other well known branded "silent" PSUs is definitely a lot 

quieter as well. 

Conclusions 

Seasonic has produced one of the most advanced PC Power Supply Unit to 

date. Its features make you ask why other manufacturers are not following suit. 

Though not as "colorful" as most new PSUs out of the market now, the 

Seasonic's beauty is within. The amount of work and technology spent in 

creating this unit guarantees its quality and reliability. At 22 dBA, it is one of the 

quietest PSU we have used ever without having to lower its fan operating 

voltage. This is an example of how you can have the best of both worlds, airflow 

and quietness. Pricewise, this unit is more expensive than most mainstream 

PSUs of the same wattage but not as expensive as premier brands with only half 

the features. For gamers and enthusiast though who don't want any non-sense 

in their system, this is an excellent buy. This has been the quietest fan cooled 

PSU we have used to date. So, if you want an ultra quiet PSU that can 

practically last you a lifetime in terms of reliability and efficiency, then the 

Seasonic Super Tornado 400 is highly recommended. It has the most features 

you can find in any PC PSU to date. 

Pros 

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Active PFC 

120mm Cyclone Cooling Fan 

Ultra Quiet 22dBA 

High Efficiency 

Automatic Smart and Silent Fan 

Control (S 2 FC) 

Honey Comb Structure 

Forward Converter 

Universal Free Input 

Dr.Cable 

3yr Warranty 

Excellent Price to Features ratio 

Cons 

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Not for show 

Needs another SATA Power 

Adaptor 

Can be Expensive for 

Mainstream 

400w may not cut it for Extreme

OCTools - Reinventing the Tools of OC - Seasonic

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