The PSU is very good, here is review http://www.jonnyguru.com/modules.php?name=NDReviews&file=print&reid=266
Like someone told you that you can use only the 4pin, but your both of MB and psu have the 8pin connector so why not use it. Also the 8pin 12v atx connector is for Ocing the cpu too because you need more power to oc. The reason they split into 2X4pin, because some of lower end MB have the 4pin only. So you can use the psu for them.