My system is at 10.7volts?

[sohcugy]

According to Motherboard Monitor my +12V rating High/Low is at 10.8V/10.7V, +5V is around 4.87/4.84, the +3.3V is at 3.28/3.26V, -12V is 0.06V/-0.18V, -5V is 5.11/5.11V. My computer is a compaq Presario SR1000Z, XP3200+, 2sticks of 512Ram, FX5500Video Card, CD player, DVD burner. I am not experiencing any lockups or anything, I ran a few benchmarks and they run fine. I do not play alot of games but will be playing WOW when it comes out. Isn't this 12V rating of 10.7 very very low? btw it's all stock Compaq including 250Wpsu. Thanks :)

[Ice Czar]

software monitoring is good for relative values
you wouldnt actually be running at those values more than likely
you would need to calibrate MBM with a Digital Multimeter to get the "real" values

http://www.hardwaresecrets.com/faqpowersupply.html

[DarkenReaper57]

A 250W PSU really isnt a whole lot for a PC. How many amps are on the 12V line? This is usually listed on the PSU itself. If I were you, I would invest in a better PSU. Running at a low voltage isn't safe, or healthy for your components.

Just my $ 0.02

[sohcugy]

Good, I thought my PSU was going out. I will get a new PSU, been looking around for one that will have atleast 14amps on the +12V for when I upgrade to a 6600GT AGP. I think I'll pop my case apart tommorow and look at it. Thanks

[DarkenReaper57]

Really, you should go for no less than 20A on the 12V line these days, imho, that way you dont need to worry about upgrading your psu anytime soon. 14A really isnt a whole lot by today's standards, either, with all of the new graphics cards coming out.

Just trying to help :)

[sohcugy]

Crap, 20A?, according to Compaq's site I have a Micro ATX chassis. Without upgrading my case( I really don't have extra cash for case+psu+and video card), I don't know if I can find one with 20A. My mother board is a ASUSTek(forgot the model number), Sandrasoft says it's model MB-1234567890 but that can't be right. I was told I could use any atx 20pin PSU, but I don't think it would fit in my case.

Alright, on my Motherboard it said MAT/NO. 145870, on the PSU it said BESTEC model BST ATX-250-127 RevisionD, 250W +12V=14A, +5V=28A, +3.3V=18A, -12V=.8A, -5V=2A. +5V&3.3V=165W, +5V&12V=218W.

I guess there no need to get a 14A when I already have one, still If I could find a 20A I would consider it, a $$$ thing. :)

[Ice Czar]

Crap, 20A?, according to Compaq's site )

POWER SHMOWER (http://www.silentpcreview.com/article28-page2.html) 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.


hense the knee jerk reaction to say you need X watts or amps
what you really need to do is run the numbers (http://hardforum.com/showthread.php?t=828901) and factor in the right windage for the supplies your considering
if youll do the basic research, I'll be back this evening and help you hunt

[sohcugy]

I used an FX 5200 card since they didn't list a fx5500 or 6600. I am not sure how much more power the 6600 is going to require but it listed,
5.7A on +3.3V, 11.9A on +5V, 14.4A on +12V, 3.3+5v = 78.5W, 3.3+5+12 combined 252W, Total 262W. So it looks lie my PSU barely supports my Computer as is, let alone with the 6600GT card. This PSU will only need to push this Computer, next one I build will be when Windows 64 will be out. This one meets specs, I know it's probably not the best, but I am looking for a Descent PSU not the best http://www.newegg.com/app/ViewProductDesc.asp?description=17-103-485&depa=0

[larrymoencurly]

Motherboard Monitor once said that my +12V rail was 10.6xV when a digital multimeter said that it was 12.11V.

[Ice Czar]

5.7A on +3.3V,
11.9A on +5V,
14.4A on +12V,
3.3+5v = 78.5W,
3.3+5+12 combined 252W,
Total 262W.

exactly what I needed ;)

well Compaq certainly sold you a supply capable of supporting the original config
it is after all in their best interest, however giving you "extra" capacity generally isnt

FSP Group (Fortron \ Sparkle) is a manufacturer, that makes reliable workhorses,
they are within spec, and conservatively rated more often than not
and get rebranded quite alot (they are a large PSU concern)

that looks like a suitable selection for the use outlined ;)
but the temperature consideration can place it near the edge
I typcally build in quite a large safety margin, youre a little closer than I personally buy at but not by much
Id just keep an eye on that on really hot days when you put it under a heavy load
simply finding a good loaction for it in a room can make a fairly large difference
(like not next to the heating vent :p or somewhere with a draft or under a window ect
give it decent room behind it, not one of those little desk hutches, or if you must exhaust such a locatiion with an auxillary fan)
or exhausting some of the air from the CPU heatsink before the PSU can (which substantially drops the PSUs internal case temprature and increases its capacity)

the difference between the theoretical maximum which is what the calculator gives
and the actual load since all the components will never actually do that at the same time is my normal safety margin, but then I deduct 1\3rd of the amps per rail a PSU is rated as well for the variable temperature potential, thus my safety margin is a bit larger, that is in this case offset partially by the conservative rating that the FSP Group generally adheres to

PSUs are all about the worse case senerio, worse possible temperature, draw of components, and the stability of the source AC power, combinations of those are where the heartbreak occurs, I always recommend investing in a UPS as well, makes any PSU perform all that much better by eliminating AC source power as a variable

Good Luck ;)

[sohcugy]

Thanks for your advice, I read through one of those articles you listed and it's scarey how much power loss is accomplished simply through a rise in Temperature. I have a portable Air Conditioner in my computer room which keeps the temperatures down to about 70-72degrees most of the time so external heat shouldn't be much of an issue. I was concerned a bit about the name Sparkle because it sounded cheap, but it had good reviews and theoretically had the power according to it's listing, anyway think I'll order it soon and get that 6600GT when they come out, :) , And I do need to find my Multimeter and check the voltage physically.

[Ice Czar]

Sparkle Electronics has a very long history with overclockers
and they merged with Fortron to make one of the largest ATX PSU concerns out there
FSP Group (http://www.fsp-group.com.tw/)

Chinese companies arent all that great a picking English names sometimes
one of the other best companies out there is called Zippy :p