Spec me EK-Supremacy + 2x Lightning waterblocks build

Nickolp1974 · 29 Jul 2012 at 14:38

X79 test bed with 2 lightnings at there stock speeds will use approx 665 watts.(100% load)
850 w psu with 85% efficiency = 722w
+ adding water, custom, not a lot i know
+ big clocks on gpu's/cpu

I'm sure 850 would be fine but i wouldn't want too! Too close to limits and a psu running close to its limits will surely degrade quicker

spixelspixel · 29 Jul 2012 at 14:40

Where did you get those numbers?

Efficiency works the other way around, if that 665 is a reading from the wall then the load on the power supply is 565w not 722w.

Nickolp1974 · 29 Jul 2012 at 14:42

http://www.legitreviews.com/article/1886/14/
Think it was from the wall, my mistake!

So is a 85% efficient 850w psu really a 1000w?

spixelspixel · 29 Jul 2012 at 14:47

Nickolp1974 said:
http://www.legitreviews.com/article/1886/14/
Think it was from the wall, my mistake!

Well there's somewhere you could save some money

A high end 850w power supply is a lot cheaper than a 1200w

And of course that x79 system will use more power than a z77.

spixelspixel · 29 Jul 2012 at 14:49

Nickolp1974 said:
http://www.legitreviews.com/article/1886/14/
Think it was from the wall, my mistake!

So is a 85% efficient 850w psu really a 1000w?

When an 85 percent efficient psu is running at 100 percent load it would be using
1000w from the wall, but it is still an 850w psu.

Check some psu reviews at http://www.jonnyguru.com ( the load testing page )

Nickolp1974 · 29 Jul 2012 at 14:57

Ahh i see, i will take a look but the man draw for me was the hopefully increased stabillity, it may make no differance and until its been tested we wont know and if it just proves to be just a gimmick then i will certainly look elsewhere. And i do thank you for your input, i'm slowly learning!

spixelspixel · 29 Jul 2012 at 15:13

Nickolp1974 said:
Ahh i see, i will take a look but the man draw for me was the hopefully increased stabillity, it may make no differance and until its been tested we wont know and if it just proves to be just a gimmick then i will certainly look elsewhere. And i do thank you for your input, i'm slowly learning!

It's not really a gimmick as some people do need a 1200w psu if they have 4 graphics cards.

But for your system 850 is the perfect wattage in my opinion even with a lot of overclocking. Anything more is a waste of money and won't give more stability. You will only have stability problems if you have a power supply which can't give enough power.

Cleeecooo · 29 Jul 2012 at 22:11

spixelspixel said:
Evek 1k is too much... 850 is more than enough enough for 7970 crossfire.

You would be surprised how little power your pc actually uses. I had a system with gtx 570 in SLI (which use more power than a 7970) and during stress testing the highest reading I ever saw from the wall was 550w ( My psu has about 85 percent efficiency so the actual load on the power supply is a mere 470w )

Using a power supply that is too big will give you bad efficiency at low loads.

well, If he does plan on possibly having 3-4 gfx cards a few years down the line, then I think a 1kw would be suitable. This is ofcourse quite a difficult thing to predict now

Nickolp1974 · 29 Jul 2012 at 22:57

Did not want to go crossfire but with the new monitor comes a higher resolution and 1 card will not do to keep those frames up at ultra (bf3), so CF will be max

A lot of people have cpu's @ 4.6+, and dont use the power unless benching but its nice to know that you have plenty in reserve, its all a man thing, we like big numbers.