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Power supply sizing - Help me with my homework

By jdclyde ·

Have never been a hardware guy, and am taking PC Maintenance to finish up my BA in Networking.

I am not looking for the answer directly, just hoping to get pointed in the right direction to get the most out of this.

The question is:

Powersupply, 450 watts. When and why would you need it.

I want to take it a step further as to the difference between rated or maxed.

What I am looking for are web sites that explain this. Where do YOU go when your looking for answers to a question like this?

Also, tools. What do YOU use to determine your power consumption so you know how "big" of a power supply you will require?


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My sources....

by JamesRL In reply to Power supply sizing - H ...
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Lots of variables

by mjd420nova In reply to Power supply sizing - H ...

Under normal situations a 450 W would do, but that's only a ballpark figure. Load in a sound card, a pair of 512 MB videocards, besides an extra large second hard drive and a DVD burner and 2GB of RAM and you're now beyond the specs for 450 W. Now I've not even touched on extra fans and such. Usage of external devices doesn't eliminate it, as the USB ports consume power too.

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by jdclyde In reply to Lots of variables

was looking for reference material to be able to evaluate and break this down on a case by case basis.

Not looking for a spoon-fed answer.

Thanks anyways.

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by Ben "Iron" Damper In reply to Power supply sizing - H ...

I go to Tom!
That would be www.tomshardware.com
I feel that this is one of THE best sites for hardware related issues.
Hope this helps.

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There are a lot of variables to be considered but ..........

by sleepin'dawg In reply to Power supply sizing - H ...

Tiger Direct has a lot of free information. If you can foresee just what peripherals you are likely to be running all at one time or might be expected to, you can add up the power requirements of each item, then add 30% for contingencies and that should tell you whether the power supply is adequate for the job or not. This still won't answer the question regarding cooling requirements but it will get you started.

Dawg ]:)

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Easy answer JD is that you would very rarely

by HAL 9000 Moderator In reply to Power supply sizing - H ...

Need a good name brand 450 W PS.

What I do is total up the power requirements of the parts used and then apply Ohms Law to the overall Amperage requirement and along with the mains voltage you get a Minimum Wattage that you'll need to run those components. The PS will add slightly more to the total as it consumes some power itself so you'll have to add some more but I think that you'll be surprised by just how little power is required to run a computer.

As for actual specifications I go to the Makers Web Site but to be honest I only ever use Antec PS as they are what I can get easily here and are very good. The better name brand PS's are rated at a constant Power Feed and the cheap ones are rated to Peek Values just like some Audio Equipment.


If I can be of any help to you just drop me a PM and I'll see what I can come up with.


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