Why such a big PSU?

NoNameNoNumber · 23 Oct 2013 at 19:15

I appreciate the more headroom your PSU has the easier life it has but what are you possibly doing with 1200W supplies!!!

I have an OC'd 2500k with a 7950, Corsair H100, 1SSD, 1HDD, 1OD and about 7 fans all running fine from a Corsair 550w PSU that has been going for 4 years now faultlessly. Shortly I'll be replacing the H100 with 18w of draw in the form an Ek 4.0 pump and I doubt I'll have any issues. Maybe 600w or so would be a more comfortable supply with this setup and if I were to crossfire the 7950 no doubt I'd be in the market for around 800w.The online calculators suggest I'm using around 300-350w

Just after your thoughts really, are we just going for much higher capacities than we need?

RJC · 23 Oct 2013 at 19:17

A lot of people over estimate the amount of power their system actually uses.

Glanza · 23 Oct 2013 at 19:20

Peace of mind.

NoNameNoNumber · 23 Oct 2013 at 19:20

RJC said:
A lot of people over estimate the amount of power their system actually uses.

My thoughts exactly. Also I think people like to think if they buy a 1200w PSU that will give them room for tri-fire Titans

NoNameNoNumber · 23 Oct 2013 at 19:20

Giggz said:
Piece of mind.

Which piece?

Glanza · 23 Oct 2013 at 19:22

NoNameNoNumber said:
Which piece?

Always one, oh look a spelling mistake quick lets pull them up on it. :rolleyes:

NoNameNoNumber · 23 Oct 2013 at 19:23

Giggz said:
Always one, oh look a spelling mistake quick lets pull them up on it.

That wasn't a spelling mistake it was just the wrong word

It made me smile anyway, I'm sorry to have offended

valkynaz · 23 Oct 2013 at 22:29

NoNameNoNumber said:
Just after your thoughts really, are we just going for much higher capacities than we need?

In general it's to do with energy efficiency. Most PSUs will operate at their best efficiency while under around 50% load. So if your system draws 500W, a 1000W PSU will provide the best energy efficiency.

Steveocee · 23 Oct 2013 at 22:32

I'd rather overbuy and know I have far too much rather than work out how much I need and get by on the skin of my knuckles.

NoNameNoNumber · 23 Oct 2013 at 22:38

valkynaz said:
In general it's to do with energy efficiency. Most PSUs will operate at their best efficiency while under around 50% load. So if your system draws 500W, a 1000W PSU will provide the best energy efficiency.

Have you got a source for this info?

Mariusz · 23 Oct 2013 at 22:55

NoNameNoNumber said:
My thoughts exactly. Also I think people like to think if they buy a 1200w PSU that will give them room for tri-fire Titans

With the custom bios the power target is lifted and a single Titan can draw nearly 500w :eek:

That's my excuse

Orionaut · 23 Oct 2013 at 23:02

NoNameNoNumber said:
Have you got a source for this info?

Look at pretty well any PSU manufacturers website. Most will have charts for efficiency vs load.

Also, everything is less stressed, runs cooler, etc

sven256 · 23 Oct 2013 at 23:16

My reason is that below a certain percent of power being used, the fan does not spin up. So in effect have a fanless psu and still have a high end system.

Also efficiency as mentioned above.

unleashed · 24 Oct 2013 at 08:37

Orionaut said:
Look at pretty well any PSU manufacturers website. Most will have charts for efficiency vs load.

A link would be good

gpuerrilla · 24 Oct 2013 at 09:39

valkynaz said:
In general it's to do with energy efficiency. Most PSUs will operate at their best efficiency while under around 50% load. So if your system draws 500W, a 1000W PSU will provide the best energy efficiency.

Not sure I agree with this statement but as NNNN points out, have you got any further info on this?

d_brennen · 24 Oct 2013 at 09:49

Th0nt said:
Not sure I agree with this statement but as NNNN points out, have you got any further info on this?

There's countless reviews and manufacturer specs out there.

>bashed Corsair into Google
>clicked products > power supplies > chose the first item
>scroll down

Being more specific, type "power supply load efficiency" into Google and read the first article from Anandtech

Scougar · 24 Oct 2013 at 10:01

Yes 1200W is excessive. It's more about wanted the best, and knowing it will cope no matter what. Voltage spikes, fast power changes are all more easily coped with by a bigger power supply (in general), and obviously... the efficiency.

Totally agree a 1200 watt power supply is almost never needed though; You would have to be running an excessive setup for that.

Stelly · 24 Oct 2013 at 10:03

The less load on a PSU normally means better efficiency. High wattage PSUs still only draw what they need.

Stelly