About processor

First and Second to which processors?

Well if you are talking about the AMD Phenoms the difference is HUGE.The second generation of phenoms are better per clock and are also clocked higher.They can also overclock very well.
If you are talking about the first and second generation of intel core i5/i7 processors.The second generation are better in every aspect and use a different platform.
Generally Newer is Better! (Excluding AMD Bulldozer vs AMD Phenom)