Difference between athlon II x4 and amd phenom II x4

Hi

I am in dilemma to buy which processor from athlon II x4 and amd phenom x4 . both processors have 4 core then what is difference ?
Some said that don't buy Amd Athlon II X4 processor but buy only Phenom X4 Athlon processor . It will be better than x4 Athlon.

hmm.. major difference is that Phenom II X4 comes with L2 cache of 4 Mb so total cache is 6mb in phenom II x4 though in AMD athlon II X2 its only 2 MB total. In simple language , Phenom II X4 is better than Athlon II x2.