so that will b enough to power both cards and all the other stuff motherboard dvd drive hard drive ect.... also whats the difference between these two motherboards besides 1 pci-e x1 and $35 http://www.newegg.com/Product/Product.aspx?Item=N82E16813136046 http://www.newegg.com/Product/Product.aspx?Item=N82E16813136047
Plenty enough, yes. The R board also has 2 more S-ATA ports and two network adapters rather than one, along with rear firewire, which it doesn't look like the RS has.
No idea on the sound card. As a general rule I always ditch the onboard sound when I game - the audio quality is fine, but it can't keep up with the number of sounds games produce at once. As for the two network ports - connecting to two networks - for example, connecting to the internet with one and connecting to a file server with the other. As for whether it's worth it, that all depends on whether you'll use those extra features. You'll have to decide on that.