Calculating my system's power consumption

[Robert Smith]

I've already read larva's "Will a XXX watt power supply run this?" post and need a bit more info. I want to upgrade my PSU to a nice quiet one, but need to know if it will provide enough power as it's output specs are just less than my current one.

I guess I should just add up the stats on each device in my PC, easy enough for my DVD-ROM as it has it printed on it: 5v - 1.5A and 12v - 1.5A, but how am I meant to find out the current flowing through my mobo and XP2000+? What about RAM and my Radeon 7500? Where can I find out the ratings for each of these pieces of kit? And is there an easier way to find out the power consumption?

Cheers

[penquissciguy]

Originally posted by Robert Smith
I've already read larva's "Will a XXX watt power supply run this?" post and need a bit more info. I want to upgrade my PSU to a nice quiet one, but need to know if it will provide enough power as it's output specs are just less than my current one.

I guess I should just add up the stats on each device in my PC, easy enough for my DVD-ROM as it has it printed on it: 5v - 1.5A and 12v - 1.5A, but how am I meant to find out the current flowing through my mobo and XP2000+? What about RAM and my Radeon 7500? Where can I find out the ratings for each of these pieces of kit? And is there an easier way to find out the power consumption?

Cheers

First off, what do you have in your computer to begin with? Amount of RAM, add-on cards, processor, drives, etc. all have an effect here. You can probably pull the specs out of the owner's manuals for most components, and there are general rules of thumb for wattage used by different devices on the web - don't remember where right off the top of my head. Also, if you're running anywhere near a sensible machine with more than a 400 watt supply, you're probably golden. My XP2100+ with the specs below, including 2 cold cathodes and 5 led case fans, is running fine on a Sparkle 300W supply. Oh yeah, branding is also important. A lot of people feel the 300W Sparkles are closer to the 350W psus of other manufacturers due to the Sparkle's higher overall output.

Another option is to beg/borrow/steal a watt hour meter designed to measure the wattage drawn by anything iwth an AC outlet. I have one (mine's called Watt's Up, there are others) that you plug into the wall, then plug your AC device into it. It will give you how much power is used by the psu as it operates. It's great because you can fire up different components and see how it changes the overall wattage used. This won't give you the usage on each line of your supply, but it will probably give you enough information to make a decision about the new psu.

Hope this helps.

Ken

[JohnnyTheRed]

Toms Hardware Guide had a general guideline for which PSU to run. A search on the forums might find it, or check out over there.