How Many Watts Does This PSU Use?

Hello, I want to upgrade my power supply on a old pc and I'm wondering which PSU to get. Please let me know what may be the max wattage on full load so I don't get a overkill psu.

My old PSU build is:

- M2N68-LA (IVY8) motherboard.

-AMD Athlon x2 5400+

- 2x 1gb RAM DDR2

- HIS Ati 4870 512mb

Keep in mind that this PC is actually a hp PC but I upgraded the CPU a while back from a old sempron to Athlon. Yesterday I found my old 4870 and wanted to see if it would fit in my motherboard an surprisingly it did, but this PC has a 250 watt PSU which I know is really low considering the gpu need more watts.

The whole pc itself is here:

Just remember it will say a Nvidia 6150se and amd sempron but I have replaced those and just want to know how many watts does my pc use now with the replaced parts

Thank you!
3 answers Last reply Best Answer
More about watts psu
  1. Almost any single video card setup uses less than 500 watts, generally shooting for something in the 500-650 range is recommended, usually you can find something that's a pretty good deal on sale in that range.

    Generally you want to look at the 12v ratings and see them somewhere at or near (within about 10%) of the advertised wattage as a sign of a recommended power supply. It's not always the case, but as a rule of thumb it will help.

    In order to find the +12v rated capacity, you just multiply the voltage by the amperage listed on the sticker, so for a 500 watt supply you look at any +12v number and multiply 12 by the amps listed for that rail. As an example: has 2 +12v rails, one 16a and one 18a, so 12 * 16 = 192 and 12 * 18 = 216, add those together is 408 watts, a good bit shy of 500, so probably want to avoid that one.

    Same as has 2 +12v rails, 17a each, so 408 watts again . . . avoid.

    Something like has a single 40a +12v rail, or 480 watts, pretty close to the 500w advertised rating, it's fine and is pretty cheap.

    As well as something like . . . single 38a +12v line, or 456 watts . . . close enough, and Corsair is generally a trusted name in PSUs.
  2. Best answer
    For a system using a single Radeon HD 4870 graphics card AMD specifies a minimum of a 500 Watt or greater system power supply. The power supply should also have a maximum combined +12 Volt continuous current rating of 30 Amps or greater and have at least two 6-pin PCI Express supplementary power connectors.

    Total Power Supply Wattage is NOT the crucial factor in power supply selection!!! Sufficient Total Combined Continuous Power/Current Available on the +12V Rail(s) rated at 45°C - 50°C ambient temperature, is the most critical factor.

    I've used one of these in that computer case:
  3. You can't generalize single gpu setups. You can have a single gpu and run off a 300w, where a 650 would make no sense at all. A 650 is enough for a titan.

    There is no telling if the amps on the sticker are peak or sustained amps. It also doesn't say how stable the power is, if it has cheap caps that will die in a short amount of time, or if it has any power protection so it won't kill your pc along with it. This is why you get a good quality psu and there is no way to know from the sticker. You could run that on a cx430 though if you wanted to reuse the psu for later, it may be better to go with a 500w.
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