How much power is needed?!

I'm sorry, but these are really bad choices. Get a cheaper motherboard, that one is ridiculous. Here's a better one with PCIe 3.0 http://www.newegg.com/Product/Product.aspx?Item=N82E168...

That saves you 150. Don't waste your money on two low end cards for CF. Get a better single GPU first, then add CF later. With the money saved from changing the mobo you can easily switch the two cards for a single 6950 2 GB which will be a *lot* more powerful.

5670 at SLI. That is the worst ever.

Thanks for the answers...
Really, there are missing some points here. As stated, the reason for the chosen mobo is because its micro-atx and still has 2x pcie-x16.
The reason for the gfx is because of the passive cooling - im looking to build a small and silent system... And with silent i dont mean, "its ok", i mean SILENT!

So 2x passively cooled gfx cards, a passively cooled psu and a huge case fan only whizzing away and cpu cooling thats inaudiable, im getting there...

So if u have better suggestions to such a system, please let me know? And how about the power - is there enough power in 500W to run this setup?

@cutebeans... According to TH 2x5670 outpeforms eg. a single HD4870/90 at half the price tag... I know there is a lot new and better cards out there, but not being a gamer enthusiast I am primarily looking for something that can perform reasonable and be silent...

If you want to objectively, accurately and scientifically determine what PSU power is required for your Vid card and PC in both watts and 12v rail amps., the forum Utility link below will show you how easy it is to calculate this information and objectively determine which PSUs are quality built, reliable PSUs that can meet your needs. Be advised that the available 12v rail amps. is just as important as the total PSU wattage. You need both to be correct.

http://www.tomshardware.com/forum/314712-28-please-read...