I've always been skeptical of information published by Thermaltake.
Both in the article provided by original poster of this thread and on Thermaltake's spec page, they put great amount of emphasis on PFC.
I hate to be so harsh, but their info about PF doesn't make sense and it's pure nonsense.
Let's go over this
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"Power factor is the percentage of electricity that is being used to do useful work. It is expressed as a ratio. For example, a power factor of 0.72 would mean only 72% of your power was being used to do useful work. Perfect power factor is 1.0,(unity), meaning 100% of the power is being used for useful work.
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This is somewhat correct, but the way it is written can be construed as rest of energy being wasted.
Power factor is the ratio of actual wattage and apparent power. It is only applicable to AC circuit and differing power factor is a result of current waveform being shifted(displacement) or differing(distortional) compared to voltage waveform.
Power factor= Watts/Volt-Ampere
A consumer grade compact fluorescent lamp often has a power factor of 0.5. This means that if the lamp is 15W, it takes 30VA. VA is simply volt multiplied by amp. If the line voltage is 120V, 30VA/120V=0.25A. You will use 0.25A from the line. If power factor was 1.0(unity), you'd draw 0.125A, although the wattage is 15W either way, so it doesn't affect your power bill at all as you're billed for actual energy you use instead of VA.
On a 5A circuit, you can run 20 15W compact fluorescent lamp with a power factor of 0.5 and you will use 600VA of utility companie's transformer's available capacity. The total wattage is 300W.
If each 15W CFL had a PF of 1.0(unity), you can run 20 while using half the capacity of transformer and circuit, but wattage will remain the same. VA will be 300VA and wattage will be 300W.
What does this mean in real life?
Wires and electrical distribution equipments are rated by amps or VA. Low power factor equipment uses distribution system's capacity and circuit capacity more than same wattage equipment with higher power factor. Distribution system's capacity is limited and upgrading is very expensive. This is a bad news for the utility company. It is also a bad news if you need to run tens of computers on one circuit as you can only run half as many computers with PF of 0.5 compared to computers with PF 1.0.
300W with power factor of 0.5 requires 600VA. This does not mean 300W is wasted.
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Power Factor Correction (PFC), then, is the method(s) used to fix the problems that cause power to be wasted."
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Again, power is not wasted. Distribution system capacity and circuit capacity is wasted. Since most home users have no reason to worry about running out of circuit capacity running tens of computers, it is mainly a concern of utility company.
I highly doubt that Thermaltake actually manufactures these power supplies. Active PFC was introduced as a solution for institutional customers running hundreds of computers and European customers. Certain part of Europe has a legislation requiring all new computers to have a power factor correction for the benefit of public/utility company. OEM manufactures simply make them when they're ordered to make power supplies that is compliant with European legislation. Keep in mind that 99% of computer power supplies are usable on 115V and 230V.
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Thermaltake claims that
"Non-PFC [power supplies] offers around 0.5~0.6 PF (Power Frequency), 40%~50% power lost. Active PFC provides more efficient PF (Power Frequency), 0.95~0.99, it means only 1%~5% power has gone."
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This means that more effective use of building wiring. This is a concern when you're running thounsands of computers on common 208Y/120V three phase distribution system and if you're an institutional customer who's billed by the utility company for having poor power factor.
In United States, only commercial, industrial and institutional customers are billed for poor power factor.
So the question is, do users here have main service as 120/240V(230V for European users) AC or 480Y/277V three phase commercial service?
If the former, you don't need to worry about active PFC unless you feel like being nice to your utility company.
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The implication is that a power supply with PFC delivers more usable power than one without it.
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No it doesn't. How much useful power it delivers is defined as efficiency, which is 60-75% for the typical computer PSU. This is not connected to power factor.
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The only thing I can see, comparing their 420 watt power supplies with and without PFC, is the non-PFC unit is rated at 10 amps and the PFC unit is rated at 8 amps - it takes less power to run the PFC unit.
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Computer PSU's seldom draw name plate current. Unlike DC circuit, V * A does not equal watts unless you have a purely resisitve circuit or something with power factor of 1.0.
120V x 10A x PF 0.5=600W
120V x 5A x PF 1.0=600W
ThermalTake puts the "Power" in Power supply
I mean...er...liars!
Linear Mode
