PSU Help!

[TheBoss68]

Ok guys...... My Enlight 420 PSU died....need to replace.....I am looking at 3.....Ultra X-Connect 500, Enermax Noisetaker 480, or the Antec Neopower.......give me some advice guys....which would be best for the system I have (see sig) and I do plan to move into an A64 proc and mobo just before or after christmas....any tips or recomendations are appreciated.

And I do overclock all the time...not just during benchies...so I need stable 12v rails and longevity here..

Thanks in advance guys!

 

[Ice Czar]

Ultra X Connect is a fancied up POWmax, so IMO thats out (besides its an ATX12V v1.3)
Antec Neopower is a damn nice supply that exceeds spec (ATX12V v2.0) with a load regulation of 3%
Noisetakers come in both ATX12V versions, if it has dual +12V rails its a v2.0
fine supplies of bacis spec compliance

 

[TheBoss68]

so the enermax being the cheaper but ust as good so long as its the v2...correct...I spent a few hours last night researching all three...and a few others....the PCP&C was just too far outta my price range...so I narrowed it to these three.....

 

[Ice Czar]

well the Enermax isnt a modular wiring harness
and has a load regulation of 5%, so the Antec does offer some advantages

I assume you have run the numbers

 

[TheBoss68]

for what wattages and such I will need right?

I figgured getting into around a 480 to 500 watt should provide me plenty for my system with much overhead for oc's
I amk running 2 hdds, 1 cdr/dvdrom, rig is in my sig....only main change will be a s939 and maybe a 3200+ or more A64 in the coming weeks.....but all in all around the same power requirmenst I'd say

 

[Ice Czar]

for the amp spread and the percentage of amps to deduct from the supplies for the difference in how they where rated and the real world operating temperature
wattage means next to nothing, the Antec and Enermax are quality supplies
but then thats not always the case

.

POWER SHMOWER by Mike Chin

or How PSU Power Ratings Mean Almost Nothing

A frustrating fact about PSUs is that there does not appear to be a stringent or regulated standard for reporting, advertising and labeling rated power. This is despite the existence of standards like ATX2.03 or Intel ATX12V.

There are well-established standards for measuring and rating HDD capacity, an engine's horsepower, or the heat generated by a furnace... but not one for how much power a PSU can deliver. There are so many cases of people with "450W" PSUs having power stability issues running a system that can't possoibly draw more than 150W. And "300W" units that keep running where the "450W" units are faltering.

It's not just about bad PSUs vs better ones. It's a dumb situation caused by uncontrolled marketing competition. Real regulation would bring PSUs out of snake oil territory and into a more sensible consumer-friendly terrain.

There are many ways PSU makers fudge to make their units seem more powerful.

1) Out and out lying. You add up the power on all the lines in many PSUs and they fall short of the rated power by 10, 20 30W or even more.

There are more sophisticated ways:

2) Limit the AC input voltage to a very narrow tolerance. The best PSUs are able to deliver their rated power given a decent range of AC input power, say 90~130V for a 120V unit. It's much more demanding to produce 300W w/90VAC input than with 120VAC, so what some PSU makers will detail in their tech specs (usually not in their consumer brochures) is to specify 115-120VAC for input power. A PSU specified this way will not deliver full power if the AC voltage sags, if there is a brown-out. Surely it causes instability more often than a PSU rated to deliver full power with 90-130VAC.

3) Specify a low operating temperature for rated output. This is quite common, but again not often seen in consumer brochures, but rather tech spec sheets provided usually only on demand by engineers or corp buyers. A typical PSU operating temp statement is somthing like this:

0ºC ~25ºC for full rating of load, decrease to zero Watts O/P at 70ºC

Examine what that says. Full power (let's say 400W) is available when the unit is at 0ºC ~25ºC. Hmmm. Think about this.

Have you ever felt air blown out of a PSU in a PC running absolutely full tilt (which it would have to do to get anywhere near 400W output) that felt cool to the fingers? 25ºC airflow would feel exactly that: Cool, given that normal body temperature is 37 °C.

So this PSU cannot deliver full rated power when its temperature goes over 25ºC. OK, what happens to the max power output capacity above that temp? It decreases gradually so that by the time the PSU temp reaches 70ºC, the PSU cannot deliver any power at all. So if you assume that this power drop as temp rises is linear, then max power capacity will drop by ~9W for every degree over 25ºC.

Now having examined as many PSUs as I have over the last 2~3 years, I have to say there's not a single PSU in ANY PC I have ever used or examined that would not measure at least 30~35ºC almost anywhere inside the PSU under almost any kind of load. And if/when it is pushed, 45ºC is nothing at all, especially for or near hot running components like voltage regulators.

So let's say 40ºC is a fairly typical temp inside a PSU. This 400W rated unit would actually be able to deliver a max of just 220W at that temp. Hmmm. Interesting, isn't it? At 50ºC, the available power would drop to just 130W. No wonder some PSUs have 3 fans each capable of 50 cfm!!

Here's a simple fact: Really high quality PSUs are actually rated for full power output at as high as 40ºC. The trick is get a hold of the spec sheets that tell such information so you can compare apples to apples. Or ask.

or

from dansdata

Unethical PSU Marketing 101.

Here's how to make overly optimistic power supply specifications. It's really simple.

First, power the thing up. You can make an ATX power supply that isn't connected to a motherboard turn on by grounding pin number 14 on the big motherboard power connector. It's easy to spot that pin, because it's the only one with a green wire going to it.

Use any handy bit of wire - like the paper clip in this picture - to connect pin 14 to any ground contact. The ground contacts are the ones with the black wires going to them. Presto, the PSU will turn on.

Now, break out your brick-sized power resistors and load the heck out of one of the output rails - the +5V rail, for instance. Measure the current as you increase the load, until the voltage sags unacceptably far below the rated voltage.

How do you tell what an unacceptable voltage sag is? Well, you could choose a nice conservative small permitted sag - say, 0.1 volts - so that your results are genuinely useful to your customers. Or you could just ignore the voltage and say that when a fuse (or some other component...) blows, that must have been the limit, right there.

OK. Now you've made a big fat amperage number for the +5V rail. If you blew up the PSU in the process, get another one, and repeat the process for +12V and +3.3V, and for the low current rails as well.

On no account, though, should you test more than one rail at a time. This is the key to the whole scam.

A big beefy PSU may be able to deliver 50 amps (say) on the 5V rail when nothing else is under load, and 25 amps (say) on the 12V rail when it's similarly all alone. But the 12V and 5V rails together may only be able to deliver, say, 350 watts between them, when they're both under load. Watts equals amps times volts.

In a real PC, all of the power rails will always be under load together.

But you're not testing what the PSU can really do - you're making pretty numbers for the sales brochure!

So test all of your rails alone, get an amperage figure for all of them, multiply that figure by the voltage of the rail it came from (the nominal voltage, not whatever the voltage had sagged to as the PSU pumped electrons through the dessert spoon you'd soldered to the circuit board), then take all of the resulting wattage figures and add 'em up. That's a wrap, folks. Ship it!

 

[TheBoss68]

the enermax i was looking at had something like 18 amps 12v1 and 14 or 16 amps 12v 2.......and the antec was like just a few amps higher on each....more what I am looking for is stability when overclocking ....no extreme voltage fluctuation like my Enlight started doing near the end...it was dropping to 11.6 and 11.7 under loads...and sitting at 11.8 at idle......I need something more constant...It is the one thing that has stopped me from getting my 2800+ to 2.7 or higher i'm sure.....the temps were fine at 2.1 vcore but it wouldn't boot to windows due to the extreme fluctuation in voltage....or so I assumed from wathing the temps and voltage in the bios...it would post at 2.7 but no windows.......but my enlight didn't last another day to study it more.......so my main rig is in the corner till I get the right PSU to drive it