What PSU do i need?

[beastin]

Hi i'm currently building a PC and need some advice on the PSU, i don't really know which i need, as i don't understand the whole 12v rail amps crap. So any help would be appreciated.

Currently questioning to get this - http://www.scan.co.uk/products/850w-xfx-p1-850s-nlb9-core-edition-80-plus-bronze-85-eff-sli-crossfire-eps-12v-135mm-fan

PC Build =
Msi P67A GD65
Intel I5 2500K
SLI 570's
8gb Corsair Vengeance DDR3 Ram
1TB Samsung f3 spinpoint 1gb
blu-ray drive
3- 230 x 30mm fans
1 - 140 x 25mm fan

Will need to power all that and all over peripherals (Mouse/keyboard/headset etc)

Thanks, any advice would we greatly appreciated.

Cheers.

 

[mosox]

That one is good. Why do you need two 570 for? Kinda overkill for any game.

 

[beastin]

That one is good. Why do you need two 570 for? Kinda overkill for any game.

I won't be getting the second one straight away, just want to make sure the psu was future proof, but thanks for the help.

 

[AdrianPerry]

GeForce GTX 570
On your average system the card requires you to have a 600 Watt power supply unit.

GeForce GTX 570 in 2-way SLI
A second card requires you to add another ~225 Watts. You need a 750+ Watt power supply unit if you use it in a high-end system (800+ to a KiloWatt is recommended if you plan on any overclocking).

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Taken from Guru3d review website, hope it helps

 

[HostileDonut]

You should be fine, but if you can, grab a 900w+ because when you overclock, you always want you PSU to have good clean power and not be working too hard.