Using a power supply with more watts than necessary?

azibux1 · 18 Jul 2015 at 16:20

Hi all,

As above, would this cause any harm?

Providing both power supplies give out 12v would this be okay just to test something? It won't be for long term use, just to diagnose a potentially faulty PSU

Thanks

NMBlack · 18 Jul 2015 at 16:29

There's nothing wrong with using a psu with a higher wattage than you 'need'.

joeyjojo · 18 Jul 2015 at 16:33

No problem for testing.

FYI PSUs produce three main outputs (12 V, 5 V, and 3.3 V) and several others.

P.S. A too-big PSU is usually less efficient (for a given price) than a right-sized one for permanent use but that's not an issue here.

azibux1 · 18 Jul 2015 at 16:41

Thanks for both answers

foster grant · 18 Jul 2015 at 16:45

I use a 1000W PSU...I know it's more than what I "need" ...but the price was good and I'm gonna use my 750W for my daughter's pc

C64 · 18 Jul 2015 at 17:52

It's a good idea as the power they can chuck out degrades over time.
Alwyas worth going for 5-7 year warranty one too.

David Bisset · 18 Jul 2015 at 18:36

My general rule of thumb is to get a PSU that will power your rig while working at 70% of it's rated capability. That way it'll be nice and efficient while flat out and not too horribad when your machine is drawing way less juice (most of the time).

Obviously different companies leave different levels of tolerance for their rated specs so it's a bit rough and ready.

Doogles · 18 Jul 2015 at 18:43

I got mine because I might not need to use all the power but at £120 it had a 10 year warranty (I didn't claim it fast enough so I think it is only 3 years) and I can use it for crossfire later on if I please. Could probably power 3-SLI 980tis but wouldn't fix my board and bottlenecked by my i5

dacads · 18 Jul 2015 at 19:00

850w is definitely more than necessary for me, but as others have said cap degradation etc occurs shortening the lifespan of the PSU. Also With 850w there's no worry if I want to crossfire my current card (unlikely) or even a new one like the 970.

David Bisset said:
My general rule of thumb is to get a PSU that will power your rig while working at 70% of it's rated capability. That way it'll be nice and efficient while flat out and not too horribad when your machine is drawing way less juice (most of the time).

Obviously different companies leave different levels of tolerance for their rated specs so it's a bit rough and ready.

Efficiency was an issue but quality units have way better efficiency nowadays, at different loads. Still it doesn't hurt leaving a bit of headroom as you don't want the fan ramped at full speed either

azibux1 · 19 Jul 2015 at 00:44

Thanks all

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