[Felix12g]

If you don't do a whole lot to max out the computer I doubt you'll notice a difference between the two bus speeds. Slower bus speeds limit how much data can cross but I don't think you'll hit a bottleneck anytime soon.

For power I've known some people with similar setups that have had problems because of a lack of wattage. Don't just let all the connections do the talking. If you do toss a second card in that computer in the future you'll pretty much have to buy another power supply to go with it. For now a 600 will probably work for you but you run the risk of all the cash for that going down the drain at upgrade time. But like I say, it'll work for that setup, you can worry about upgrades after that one's built. Make sure to check alot of reviews on the hardware, not just the comments on newegg. I can vouch for the quality of thermaltake (Though they are a little more expensive), they're known for it, but getting a cheap power supply can come back to bite you.