# How many Watts do i have now.

#### Untruest

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It's a simple question that i am sure has been answered many times before but for some reason couldn't find it is, What is the max watts my ps can push?

I just need a formula or directions or something.

I took physical science before and from that i learnt volts * amps = Power(watts) But that didn't make any sense. so please help.

BTW i don't want to go about doing it backwards where i approixmetly calculate how much watts my pc is using now and assume from that number that i can put in a nother component.

Thanks again

#### RichPLS

##### Champion
i learnt volts * amps = Power(watts) But that didn't make any sense.

Why not?

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#### fishmahn

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Aaaahhhh, the ultimate PS question.

Some mfg's give their power supply a true rating that it can handle over the long haul. Others are rated at peak, but only 70% of that long haul. Others are 60% long haul, or 80%, or... Others really reach and have trouble putting out the rating in the first place.

Then there are those that use components that can handle the load today, but burn out after several months, or a regulator burned out and the voltages could be so unstable so it's worthless.

Then there's the question of how much power is drawn on any particular line - 12v, 5v, 3.3v, and their negatives, and how much draw the PSU can handle. I don't think any one person really knows the answer to that question. I know I don't.

So, to try and answer your question, assuming a quality "true" PSU, it can push the wattage rating, but limited by the individual voltage rails as the label states (i.e., 3.3v can do 30A, so it can handle 100w, 5v can do 28A, so it can handle 140w, the 2 12v lines can handle 14A & 15A respectively, totalling 168w & 180w ea.), with a further limit by summing some rails (3.3v + 5v limit 150w). The above are for a FSP400-60THN from the picture at newegg <A HREF="http://www.newegg.com/app/Showimage.asp?image=17-104-935-06.jpg/17-104-935-02.jpg/17-104-935-03.jpg/17-104-935-04.jpg/17-104-935-05.jpg&CurImage=17-104-935-03.jpg" target="_new">here</A>

Mike.

#### Untruest

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You said you don't know the answer to my question, But is it right to assume i can add up the watts to make my total watts?

If not which one should i most be concerned with (i.e 5v, 3.3v)?

#### fishmahn

##### Distinguished
Roughly, yes, making the assumption that the mfg reported the actual output. But that's limited by the total output rating of the PSU. (i.e., if the sum of the 3 main voltages total 560w, but the PSU is rated at 400w, then it can only put out 400w - maybe...)

For most modern processors and graphics cards, the 12v is becoming the most important.

Mike.

#### Untruest

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Ok, then that's not really helpful ( really it is though) because it will add up to more than 400 but i don't know what the rated watts is, and that's what i am asking.

If it helps, i have a celeron 800mhz fsb-100mhz.
What were psu's usually rated at in the time.

#### mozzartusm

##### Splendid
The bottom line is that because there is not a really good standard that PSU makers have to follow then the numbers on the box usually mean squat.

This is simple though. You must buy a PSU from one of the manufactures that has a good and solid reputation. How much money do you have to spend on a PSU? If you will tell me that then I will give you some links for PSU's that will do the job.

To save us both time, assume I know EVERYTHING :tongue:

#### fishmahn

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What Mozz said, mostly...

If it came with a case bought separately, or from a smaller vendor, then it's probably a 300w, maybe, though not real likely, 350w. It could even be as low as 250w. If it came from something like Dell or Gateway, then it's probably less - 250w. What are the 3.3, 5 and 12v ratings? That may let someone hazard a more educated guess.

Maybe the better thing to do is for us to find out why you need to know - do you desire to replace the mobo/cpu and use the existing PSU, or just add a device, or run a watercooling setup off it, or... ?

Mike.

#### mozzartusm

##### Splendid
Good point

To save us both time, assume I know EVERYTHING :tongue:

#### _WW_

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<A HREF="http://www.jscustompcs.com/power_supply/" target="_new"> Power Supply Wattage Calculator </A>

....WW (5.0)

#### Untruest

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The reason why i wanted to know how much my PSU was pushing, is to know what can i do to it. I am not intending on buying a new PSU unless i get a new system.

I planned on adding fans and o'cing the thing.

The minimum recommended watts is 200.

so as u can see, if my power supply is pushing 250w ( because i really doubt 300w) it is really close to 200 and it's a cheap one. I DOn't even know what it is.

#### fishmahn

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Is there a brand and model # on the label that displays the amp ratings?

Adding a few fans is probably not a problem - they don't generally run more than a few watts each so I would consider it 'incidental' unless it's more than just a few. Overclocking however, may be a bit more, depending on how much and what you do.

I can't see more than a few watt's extra draw from bumping the fsb from 66 to 75 or 83 (I bet regular math applies there), but if you're going to change the vCore, then it adds more than that because of power loss from the regulators - could be 20%, could be 50%, I don't know...

Mike.

#### Untruest

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it's an ATX 320 model (what ever that's suppose to mean) and there are information about amps to volts.

So i plan to oc to 133mhz FSB and add about 2 to 3 fans put ram at pc133 and buy a new video card(pci).

#### fishmahn

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The ATX means the PSU complies with the ATX standard for power supplies, which defines the parameters of the unit - the fact that it uses a 20-pin mobo connector, has both HDD and floppy connectors, as well as other things like the shape and size, etc.

The 320 is probably the 'rated' wattage of the unit.

Mike.

#### Untruest

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ATX, i already knew what it meant and if 320 W is my rated watts, then that would be sweet. But yet i really doubt it is but possible nontheless.

I doubt because i am on a celeron 800mhz s370.