APFC Power Supplies

DarkNMSS · Post by **DarkNMSS** » Sun May 18, 2003 1:33 pm

It seems that APFC power supplies are supposed to run more efficiently, but that's only at higher loads isn't it? So if I use my computer mainly to surf the web and occasionally play games, will it be worth my while to obtain an APFC power supply? I don't tend to leave my computer on 24/7 so I don't really know if a normal power supply will last long enough to pay itself off in the long run.

Does anyone use a modded APFC Seasonic PSU? How quiet do these things run when compared to stock units of any brand.

Thanks

Post by **MikeC** » Sun May 18, 2003 1:43 pm

DarkNMSS wrote:It seems that APFC power supplies are supposed to run more efficiently, but that's only at higher loads isn't it? So if I use my computer mainly to surf the web and occasionally play games, will it be worth my while to obtain an APFC power supply? I don't tend to leave my computer on 24/7 so I don't really know if a normal power supply will last long enough to pay itself off in the long run.

Does anyone use a modded APFC Seasonic PSU? How quiet do these things run when compared to stock units of any brand.

Thanks

Efficiency refers to AC/DC conversion efficiency. It has nothing to do with Power Factor. The result of poor PF is "harmonics", which makes the load more difficult for the electric power company to drive. The result of poor efficiency is more heat in the PSU.

I use many modded Seasonic PSUs. How quiet they -- or any modded PSUs -- run depends on how you've modded them

If you do a Panaflo M swap, cut away the fan grill and open up the intake grills, they remain super quiet even in excess of 100W DC power delivery. It's slightly quieter with a Panaflo L, but not as cool (or as safe, therefore.)

I think this may be quieter than any production fanned PSU in actual operation because of their internal thermistor's very carefully customized thermal/fan voltage curve.

halcyon · Post by **halcyon** » Mon May 19, 2003 7:32 am

Thanks for the information Mike.

I take it that Seasonic APFC (with S2FC) models are not particulary silent with the stock fans, when the load is 75-100+ watts?

Also, can you state with what kind of case temps have you tried your M modified Seasonic with?

Thanks.

Post by **MikeC** » Mon May 19, 2003 7:55 am

halcyon wrote:I take it that Seasonic APFC (with S2FC) models are not particulary silent with the stock fans, when the load is 75-100+ watts?

Also, can you state with what kind of case temps have you tried your M modified Seasonic with?

Thanks.

The stock Seasonics are quiet up to ~100W or more, because the fan voltage hardly increases past 5V till over that. The starting voltage is 4.3V, typically. The main issue I have is the fan itself, which is a 0.25A Adda ball bearing that chatters a bit. Not a great fan for low noise. With this fan fan, I measured 19~20 dBA @ 1m in the anechoic chamber. This is very similar to the Zalman 300 (which ramps up much faster in speed). Compare that with 18 dBA for the sleeve bearing Seasonic 300W (non-APFC) and Nexus NX3000, and <14dBA for the SilenX 400 by ExoticPC. (All at minimal load). I know that the Seasonic is the slowest to ramp up its fan voltage. (Yet it gets to 12V past 180~200W DC output -- undertypical temp conditions -- for very good cooling when needed)

Case temps -- probably in excess of 45C, but I try to keep it under 40C. The 2 that are on in front of me right now are at 34C and 37C.

halcyon · Post by **halcyon** » Mon May 19, 2003 7:58 am

Thanks again Mike. Your hands on gathered experience is very valuable.

I just found a review of the SS-400 APFC model that doesn't give too high remarks for this PSU:

http://www.modsynergy.com/Review%2015.htm

You didn't find any stability problems with your systems? Did you use the APFC units at all?

Sorry, so many questions

regards,
Halcyon

Post by **MikeC** » Mon May 19, 2003 8:13 am

halcyon wrote:Thanks again Mike. Your hands on gathered experience is very valuable.

I just found a review of the SS-400 APFC model that doesn't give too high remarks for this PSU:

http://www.modsynergy.com/Review%2015.htm

You didn't find any stability problems with your systems? Did you use the APFC units at all?

Sorry, so many questions

regards,
Halcyon

That review is nothing like I what experienced in over a year of using various Seasonics. I have probably gone through a dozen or so samples -- 300, 200, 300/400APFC -- and have several working in systems in the house right now. I think the ARM System I reviewed also used one -- a 350W? I brought some in because I like them, and have used them in some systems I built for friends, etc. Certainly, there was variance in some samples, but that kind of instability? No, not, even after abuse and mods. I would personally take a SS over an Enermax ANY day. The latter is overrated and not well designed, IMO.

halcyon · Post by **halcyon** » Mon May 19, 2003 10:59 pm

I just got the efficiency figures for the Seasonic SS-350FS (active PFC) power supply. Figures are efficiency at full load as offered to me by the manufacturer:

70~71% for 115v 60 Hz
74~75% for 230v 50Hz

The figures should be for power supplies being shipped now. Still not quite there in the 80% that some retailers list on their sites, but slightly better than what Fortron gives to their own power supplies.

regards,
Halcyon

alexb · Post by **alexb** » Fri May 30, 2003 1:56 pm

halcyon wrote:I just got the efficiency figures for the Seasonic SS-350FS (active PFC) power supply. Figures are efficiency at full load as offered to me by the manufacturer:

70~71% for 115v 60 Hz
74~75% for 230v 50Hz

The figures should be for power supplies being shipped now. Still not quite there in the 80% that some retailers list on their sites, but slightly better than what Fortron gives to their own power supplies.

regards,
Halcyon

Where did you get those numbers? Their own website only states >65% for 110V?!

halcyon · Post by **halcyon** » Fri May 30, 2003 2:41 pm

Straight from the source. I mailed them.

Mike had written in the review they they were going to try and get the efficiency up on later models.

I wroter them and that's what they replied to me. Of course, it's manufacturers own info, so take it for what you will.

regards,
Halcyon

Harry Azol · Post by **Harry Azol** » Fri May 30, 2003 6:25 pm

MikeC wrote: I would personally take a SS over an Enermax ANY day. The latter is overrated and not well designed, IMO.

Would you mind elaborating? Just curious because I'm using a Enermax 350w whisper (whisper my @ss!) with the 80mm fan replaced with a L1A

aphonos · Post by **aphonos** » Fri May 30, 2003 6:43 pm

Harry Azol wrote:
MikeC wrote: I would personally take a SS over an Enermax ANY day. The latter is overrated and not well designed, IMO.
Would you mind elaborating? Just curious because I'm using a Enermax 350w whisper (whisper my @ss!) with the 80mm fan replaced with a L1A

Mike may provide his own answer, but I think the part of your quote that I bolded hits the nail on the head. If you haven't already read them, Mike's Seasonic SS-300FS: Quiet Power Supply and the Recommended Power Supply Units article will likely shed some light on his preferences.

Harry Azol · Post by **Harry Azol** » Sat May 31, 2003 9:19 am

aphonos wrote:Mike may provide his own answer, but I think the part of your quote that I bolded hits the nail on the head. If you haven't already read them, Mike's Seasonic SS-300FS: Quiet Power Supply and the Recommended Power Supply Units article will likely shed some light on his preferences.

Well, I wanted more information on the "not well designed" part, the noise can be easily taken care of by replacing the fans..

Post by **MikeC** » Wed Jun 11, 2003 1:08 am

Harry Azol wrote:Well, I wanted more information on the "not well designed" part, the noise can be easily taken care of by replacing the fans..

1) They use 2 fans because they have to - so it seems. They're absolutely paranoid about overheating. The fan that is manually adjustable is tied to the thermistor so its minimum speed rises the longer the PSU is on such that in normal operation, you often have only med to high speed range on the knob.

2) I had 2 Enermaxes which died from overheating. One was with a Panaflo mod & the 92mm fan pulled & its hole covered up; one was using the original fans (both) but with the thermistor not glued to the coil. My guess is that there was still 25 cfm going through the 2nd one, you could really feel the airflow. But it got really hot all the time -- the exhaust air, I mean.

3) I measured the efficiency of one before it died and it never reached 70% at any power level, which is pretty bad because almost every PSU I've measured get up above 70% at some point another, so this suggest low efficiency, which suggests high heat.

4) They are such a mess inside. I am not an engineer but I know and have worked with lots of them. MOst would not consider the layout/design of the Enermax to be clean or efficient. That convoluted fan controller desgin is enough to make me starting shaking my head anyway.

So that, in essence, is why I think they are not well designed. They are a big contrast to the rugged build of the Fortron-based models or the clean tidy efficiency of the Seasonics.

Harry Azol · Post by **Harry Azol** » Wed Jun 11, 2003 8:10 am

Wow, I've always suspected that they weren't the best PSU's, but I didn't think they were that bad.

Which models were they exactly? Thats very different from my experience with my EG365P-VEFC (I hope thats the right model number).

It's about 2 years old now, but different from the newer Enermax's with the same model #.

Mine has no manual fan control, it had a 3 pin connector for the rear (exhuast) fan so the MB could power it on/off and monitor RPM, and it was regulated by a long thermistor which could be placed anywhere in the case. I replaced that fan with a L1A @ 12v, and left the 92mm fan as is, since it doesn't seem to make any noise compared to the L1A ( obviously not running at full speed, but I couldn't find any thermistors on the heatsinks inside the PSU?).. I also covered up the front vents of the psu, and the air exiting from the PSU is cool and seems to be the same temp as the air exiting from the L1A under the psu (my only case fan)

Post by **MikeC** » Wed Jun 11, 2003 8:41 am

Harry -- they were both 365s, one w/o any external thermal or speed controls, the other with a manual speed control Can't recall model numbers. I am not condemning all Enermaxes or anything, but as there are so many better options for quiet PSUs these days, why bother is my attitude. If you have a good one, hey, hang on to it!

I remember reading about that external thermistor-on-wire model. I wonder if it IS the only thermistor in it? The default / start voltage must be fairly high and the trigger temp fairly low if it is the only thermistor (in case someone does something like put it outside the case where it's always 20C, for example). Or maybe it controls only one fan & the other is at a fixed voltage. I think the 92mm fan on one of mine was like that.

Harry Azol · Post by **Harry Azol** » Wed Jun 11, 2003 9:13 am

The external thermistor only controlled the 80mm fan. They took a 80mm fan with 3pin connector and thermistor, put it inside the psu, and ran the wires out of the psu so you could power the fan and place the thermistor wherever you wanted to

One of these days when I replace my noisy WDs with a Seagate, I will do a little more investigating inside the psu to see how the 92mm fan is controlled.. I'm not very motivated right now, because the WDs are so LOUD now after I modded the "whisper" psu

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