Help w/ high-end PSU

[Mercutio]

A while back I mentioned that I wasn't able to use the second core in a couple of my x2-based machines, but if I let the machines run on non-SMP kernels, they still worked OK.

Over the weekend I got around to correcting that - I put in 520W OCZ-something-or-other. It had lights inside it. I should've known it would be a steaming pile.

But I went with it, since I had the PC apart and all.

... and today the OCZ PSU flamed (flamed!) out. Like, there's a dark spot on my wall from the FIRE.

So it's going back to my disti. My disti stocks HEC (which I like and which normally work fine, but don't come in sizes bigger than 450W) and ThermalTake (the biggest they stock is 460W), and some crap-brands (Elements) that claim to be up to 600W and cost as much as a 450W HEC.

And I'm looking at replacements from a couple places online that have a better selection of parts. I'm wondering about some of the characteristics of these high-end units, particularly the significance of multiple +12V rails (are they a good thing or a bad thing? I notice that the lower-end PCP&C units don't have them, but high end Antecs, Enermax and Seasonics do) and "PFC" support.

Can someone explain these things to me?

 

[CougTek]

PFC stands for power factor correction. Also, multiple 12V rails is good because it isolates each line, so there's less ripple on the current of each line. When a device draws juice from any given electric line, it creates a distortion. The more devices sucking current, the worst it gets. Having multiple isolated lines lesser that effect.

 

[Mercutio]

Thanks.

Looks like I'll be better off with a multi-+12V Enermax PSU than a low-end PCP&C then.

 

[CougTek]

Seasonic S12-500 and S12-600 are sent by angels. The Enermax aren't bad, but they aren't in the same league. They probably cost a lot less though.

 

[jtr1962]

To explain PFC in more detail, as you may know the power used by our PCs starts off as 120VAC, 60Hz. 120VAC is a sine wave with 60 cycles per second and a RMS (root-mean square) voltage of 120. Now the interesting part. If you've ever had introductory courses to electrical engineering I'm sure they covered reactive loads (i.e. capacitors, inductors, or any combination thereof). These loads are called reactive because they can store energy unlike a passive load such as a resistor. Granted, the energy storage isn't of the order of magnitude of a battery, but it's enough to alter the current waveform. If you drive a pure capacitive load with an AC voltage, the current flowing to the load will lead behind the voltage. In on the other hand the load is purely inductive the current lags the voltage.

What the above means in practical terms is if you try to figure out how much power the load is using by multiplying the RMS current by the RMS voltage then the result, called the apparent power, will be too high. This is where the term power factor (PF) comes in. A load with an apparent power of 200 watts but an actual power of 100 watts will have a power factor of 100/200, or 50%. Actual power is found by using a watt meter which multiplies the instantaneous values of voltage and current rather than the RMS ones. A low power factor load means that more current is flowing in the AC lines than otherwise needs to. This is bad because losses are proportional to current squared. Lower power factor equals more losses. In fact, industrial customers are billed more for low power factor loads. Regardless of whether you're billed for it or not, higher power factor loads reduce line losses, and save energy. Power factor can obviously never be greater than 100%, although it is exactly 100% for purely resistive loads such as heating elements. It can be way less than 100% for anything inductive or capacitive. Power supplies have both types of loads. Fluorescent light ballasts are also inductive. PFC seeks to reduce the power factor to some value closer to unity. Active PFC is obviously best, but passive PFC can do pretty well for constant power loads such as lighting.

 

[Groltz]

The Seasonic S12-600 is an excellent unit.

Very quiet too.

 

[Mercutio]

Maybe my next one. I bought an Enermax 600W unit about two minutes after Coug's reply.

 

[CougTek]

I knew that the kitty wouldn't resist to reply to this thread. I almost restrained myself from replying to Merc because I knew my answer would look piss poor compared to the detailed reply JTR would subsequently post.

I feel I helped a little anyway. I gave the conclusion while JTR threw the whole dictionary ;-)

BTW, no need for an engineering class to know about reactive loads. My collegial class teached me all that, but it's quite far in my memory since I no longer use it, unlike feline '62.

 

[Santilli]

If you look at the reviews, the Seasonics are in a league of their own as far as consistent energy supply.

They are also very quiet, and very expensive, if not bought on fire sale.

Somewhere around here, I did a real indepth research on these things, and found out the others aren't even close.

GS

 

[jtr1962]

I knew that the kitty wouldn't resist to reply to this thread.

Meow. ^^ :cat:

BTW, yes, the Seasonic are in a league of their own. I've been using a Tornado Super Silencer with active PFC for the last 2 years. Very quiet, very stable, and a claimed 0.99 PF.

 

[The JoJo]

That does it. I'm replacing my Nexus 350W with a Seasonic 500W tomorrow. Been looking at the reviews at silentpcreview for a long time, and drooling over them due to them being so quiet.
Running my P4 3.2@3.44 24/7 makes the Nexus quite loud.

 

[jtr1962]

It's not just the low noise level which is great about Seasonics, but also the efficiency. Mine gets close to 80% according to the silentpc reviews. The latest ones get close to 90! Don't be surprised if in a few years they reach something like 97% or 98% efficiency. That could mean they won't need fans at all!

 

[Handruin]

Isn't it true the PFC has no effect on your power bill based on the way the utility company rates home electricity? I realize the increased effecincy is the true savings, but in terms of PFC, isn't there a savings for businesses who are changed at a different rate?

 

[Gilbo]

I've always used Fortron power supplies. The FSP300THN (their 300W ATX12V 2.0 supply) has always been dead silent in my configurations. They aren't overpriced and they're rock solid. I'm sure the Seasonics are nice, but I can't see myself ever spending anything close to that for a quality power supply especially when the Fortrons are so good.

OTOH, I've never had to use a large wattage PSU. I suppose they need more cooling. I don't know how the FSP 500W would hold up in terms of noise to a Seasonic.


Handruin, you're rate about PFC. Only large commercial consumers are charged on PFC. In some cases, it can make about the major cost for their electricity. However, managing the consequence of power-factor is a significant cost to utility companies. Everyone's electrical bill goes down if PFC power supplies become common place.

 

[Mercutio]

FSP Group is the company that makes Sparkle power supplies. They're all very noisy. I don't even think they make a low-noise model.
On the other hand, they're reliable as all get-out.

 

[CityK]

Dandata had a look at PFC a while ago....always a good read.

 

[Buck]

Dandata had a look at PFC a while ago....always a good read.

Thanks for the link CityK.

The difference between car salesmen and computer salesman is that car salesmen know when they're lying, so someone who tells you Active PFC makes a PSU more efficient is not necessarily trying to pull the wool over your eyes. You'd still probably do well to buy from someone else, though.

 

[Pradeep]

I believe multiple 12V rails have something to do with UL listing.

 

[ddrueding]

IIRC, multiple 12V rails is required in the newer ATX spec. Therefore getting one is futureproofing in some way.

 

[Pradeep]

There's a UL/CB safety reg that you cannot draw more than 240VA from any single rail of a user-accessible power supply. So to get more than 20A, you need multiple 12V rails.

 

[BooST]

PC Power and Cooling (If you REALLY need some juice), Otherwise Enermax/Antec or bust. Crappy power supplies = crappy computers. The most important component in a PC IMO. Make sure you don't skimp, but I know that you won't.

 

[The JoJo]

Found a Seasonic 430W, WONDERFUL thing! Very low noise, just what the doctor ordered for my PC.

 

[Bozo]

I usually buy Antec power supplies. I'm looking to buy a new supply with PFC. The Seasonics are nice, but a little pricey.
I was reading the comments (at Newagg) about the 500W Antec and it seems there are problems with this power supply and some motherboards. Does anybody know of this problem, or is it an isolated case?

Thanks,

Bozo :mrgrn:

 

[mubs]

I read the reviews at Newegg, and it looks like Seasonic's quality swings wildly back and forth. Quite a few DOA units, many units dying after a day or two. Anybody care to comment?

 

[ddrueding]

I've purchased a dozen or so Seasonic units and have had no complaints. I do tend to oversize significantly (a 350W PSU is huge for most of my single-dive systems).

 

[mubs]

Thanks Dave.

How does one size the +3.3v, +5v and +12v rails? The various online PSU calculators only spit out the aggregate power required. My concern is undersizing one of these crucial rails.

Let's say the system would be:

A64 X2 4800
Nforce4 Ultra (non-SLI) motherboard
Radeon x1600 XT PCI-E
4 sticks of RAM
Sound card
Video Cap Card

I have no idea how many amps these things would suck off each rail. HDDs, Opticals, etc. can be figured out from their data sheets.

Among 600 Watt PSU's, the 3.3/5v combined wattage ranges from 180 to 282; the 12v wattage for these same units ranges from 400 to 480. That's a pretty significant variation for units with the same nominal wattage.

TIA!

 

[MaxBurn]

PC Power and Cooling (If you REALLY need some juice), Otherwise Enermax/Antec or bust. Crappy power supplies = crappy computers. The most important component in a PC IMO. Make sure you don't skimp, but I know that you won't.

Another vote for PC Power and Cooling, have them in a couple servers with stacks of HD's and never had a problem with one. I am pretty surprised they didn't get more votes.

Because I have a couple Antec cases I have their power supplies in those computers, should be fine for most of the desk tops out there. Had an Enermax once too, it worked fine in a reasonably high end machine as well.

I don't buy crappy cases or when I do I avoid the ones with a power supply included and get something decent.

 

[ddrueding]

Mubs,

The rail tou care about in that system is the 12v rail (for both the CPU and video card) and those 600W PSs that you're looking at are about double what you need in my experience. If you get Seasonic's 400W you should be fine. How many hard drives?

 

[mubs]

Thanks, Dave. 2 x SATA HDDs, 2 x Opticals, 1 x FDD, 4 x 92mm case fans, 1 x fan controller, 1 x USB/FW front panel bay.

I thought the CPU ran off the 3.3v rail? I know the P4 requires a dedicated 12v rail, but didn't know A64's used 12v as well.

Of the brands I've checked (Seasonic, Antec, Enermax, PCP&C, Thermaltake), Enermax take the top 3 spots for highest (3.3v+5v) wattage and 12v wattage. On Paper, that is. Followed by Seasonic, with Antec immediately behind.

Brand-Model             Nominal  3.3v Amps  5v Amps  Max 3.3v+5v Watts | Max 12v Amps  Max 12v Watts
Enermax EG701AX-VE (W)   600        34        34          282          |      35           420
Enermax EG701AX-VH (W)   600        32        32          265          |      35           452
Enermax EG851AX-VH(W)FM  660        38        42          240          |      35           480
Seasonic SS-600HT        600        30        30          180          |      36           432
Seasonic S12-600         600        30        30          180          |      33           400
Seasonic SS-500HT        500        30        30          180          |      33           396
Seasonic S12-500         500        30        30          180          |      25           300
Antec NeoHE 550          550        24        20          179          |      42           504
Enermax ELT620AWT        620        28        32          170          |      36           432
Antec NeoHE 500          500        23        17          161          |      38           456
Enermax ELT500AWT        500        28        30          160          |      30           384

Disappointingly, PCP&C and Thermaltake do not quote max wattage/amps for the 12v and (3.3v+5v) rails. Many do not quote a warranty on their web site. Very few quote efficiency, ripple, regulation and PFC.

 

[mubs]

Ack! Got wrapped! Looked ok in preview. Sorry.

 

[jtr1962]

Another vote for PC Power and Cooling, have them in a couple servers with stacks of HD's and never had a problem with one. I am pretty surprised they didn't get more votes.

How are those in the noise department? One reason I'm sold on Seasonic is their very low noise level. Despite the low noise, the 120mm fans they use manage to move enough air that I was able to dispense with case fans without any problems.

 

[P5-133XL]

PC Power & Cooling tend to be on the loud side: Even their so called "Quiet" models are, to me, quite noisey. However, I have done some simply surgery and swapped out the fan for a quite model a similar CFM with great success. However, I do recognize that I voided the warrentee while doing so.

 

[sechs]

If you're willing to pony-up, PCP&C will do a custom fan for you, so as not to void the warranty.

 

[MaxBurn]

Yes, the PCP&C is rather noisy. I will try to keep seasonic in the back of my head for the future desktops.