Bottleneck + motherboard question

so, i am going to go for a phenom ii x4 965BE (http://www.newegg.com/Product/Product.aspx?Item=N82E168...) and a radeon 7770 (http://www.newegg.com/Product/Product.aspx?Item=N82E168...). i would love to run skyrim on medium and MAYBE high settings with a budget of <$650. im planning on getting this aftermarket cooler (http://www.newegg.com/Product/Product.aspx?Item=N82E168...) to overclock the CPU with hopefully no bottleneck. the question is, how bad will the bottleneck be if any? second question is - is the framerate/quality any different if i use a pci express slot 2.0 (http://www.newegg.com/Product/Product.aspx?Item=N82E168...) with a pci express 3.0 card? thanks so much!