Is this true about PFC

RaNDoMMAI · Post by **RaNDoMMAI** » Thu Dec 30, 2004 5:33 am

Power Factor Correction makes the utilities companies happy, but it certainly doesn't SAVE you energy. Industries get billed by power factor, but home users only get billed by KWH, so power factor correction doesn't help you.

Actually, active power factor correction will COST you more, since it sucks a bit of power to fix the signal.

http://www.dansdata.com/gz028.htm

It's still a very nice PSU, but I just thought I'd clear up the misconceptions about power factors

jagec said that over at anantech http://forums.anandtech.com/messageview ... erthread=y

how much more would it cost upgrading to a seasonic if this is true?

~RaNDoM

Dhurdahl · Post by **Dhurdahl** » Thu Dec 30, 2004 5:48 am

Intresting post....

True yeah kinda.. What the author forgets is that a normal appartment/house isn't just that PSU and nothing else... its alot more, including your neibours
The more crap each component feeds back into the powergrid the higher will the powerdraw be in total due to lost effectivity.
Also to remember... it's not just you and the power/filter station... it's ALOT of people normally that all feed crap back to the grid.

The more crap on the line the more expensive filters/compensators do the power company need to buy... thus the higher the cost for each subscriber..

So... when does the PFC+extra power cost for the PSU outweight the raised cost for power in total.... no idea.. no clue at all.
But personally I run active PFC on all my PSUs..

Post by **Rusty075** » Thu Dec 30, 2004 6:53 am

A-PFC will cost you a percent or 2 in total PSU efficiency. Probably about a watt more AC draw, typically. ( or about $0.005 more per month, for a typical PC, running 24/7, and paying typical electrical utility prices, if I did the math right)

But saying that PFC only saves the Utility money, and not you is a bit short-sighted. Anything that costs them money, costs you money, via increased utility rates.

meglamaniac · Post by **meglamaniac** » Thu Dec 30, 2004 9:43 am

Which is why in the UK and Europe, passive PFC is the minimum required by law and active PFC is therefore preferred for efficiency.

Beyonder · Post by **Beyonder** » Thu Dec 30, 2004 10:00 am

Rusty hit it right on--a cost to your utility company is always going to be absorbed by you in some manner.

It should also be noted that PSUs lacking APFC pollute the mains. If you do any powerline networking, it's possible that your computer can degrade the signal between nodes simply because it's creating noise on the powerline.

greeef · Post by **greeef** » Thu Dec 30, 2004 11:59 am

probably makes your speakers a bit noisier as well.

lenny · Post by **lenny** » Thu Dec 30, 2004 12:30 pm

Rusty075 wrote:But saying that PFC only saves the Utility money, and not you is a bit short-sighted. Anything that costs them money, costs you money, via increased utility rates.

To play the devil's advocate:

Let's say using no PFC instead of active PFC cost the utility $10 more, but saves me $1 per year.

They're going to spread out this $10 among their 500,000 (or whatever) customers, and I end up paying less than 1 cent more, while saving $1 per year.

Yes, this is a totally selfish, short sighted way of thinking. Unfortunately that's how many people are going to decide.

I've already decided that my next power supply is going to be active PFC only. So it looks like its going to be the Seasonic (which also has fairly decent AC - DC efficiency) instead of the Antec Phantom.

Spinner · Post by **Spinner** » Thu Dec 30, 2004 1:08 pm

But active PFC also acts as a very good power regulator, and that probably improves the durability of all the computer's components. Wouldn't that be worth the small efficiency trade-off?

RaNDoMMAI · Post by **RaNDoMMAI** » Thu Dec 30, 2004 9:09 pm

thx guys, the more info i learn the better.

~RaNDoM

Operandi · Post by **Operandi** » Fri Dec 31, 2004 8:33 am

Dose anyone know how much of an impact APFC has on battery backups?

Edward Ng · Post by **Edward Ng** » Fri Dec 31, 2004 8:46 am

If you use a Power Angel or Kill-A-Watt you'll see that PFC directly cuts down on VA drawn, so it allows for you to either use a lower VA/cheaper UPS or to get more run time out of your UPS; actually this is the most noticible benefit from using PFC for American users, but only if you use a battery back up. My main reason for having PFC is because the circuit breaker to my testing area is low current (20 measly amps) and if I have three or four computers on at once along with the A/C during summertime, I tripped the breaker a few times; switching to Active PFC on three of the computers fixed it; haven't had a breaker jump except one time when somebody ran the microwave too (kitchen is on the same breaker as myself, and so it includes the microwave, refrigerator and exhaust hood).

-Ed

wing · Post by **wing** » Fri Dec 31, 2004 8:48 am

I don't know how much impact APFC has on battery backups, but it seems that not all APFC units are created equal. My "old" (less than 2 months) Silverstone SST-40F would do weird things to my UPS, but so far I've had zero problems with my new Seasonic. Both have APFC.