Cpu Fan Temp + Rpm, Maybe a Problem?

I have just finished my first custom gaming build and i am unsure that my temps are 'ok' standard, i have 5 case fans and a cpu fan but my bios says that the cpu temp is 48c which after a quick search of the net showing i should have around 30c idle :/ my fans are showing that the speed is 1130rpm which seems to be low looking at other peoples i'm not sure how to change this so that i can get higher speeds, also the other fans are on 1600-1700rpm, my mobo temp is at 20-23c which i think is fairly ok, just the cpu. should i consider buying buying a new one? btw its not stock its a 'arctic cooler freezer 7 pro'