i would say the core i3 by far. the athlon II x2 250u is an ultra energy efficient cpu. while not a bad cpu at all and very good for daily use, the 250u is only 1.6 ghz. the i3s are dual core but the hyperthreading can make it "act" as a 4 core with certain apps. Benchmark results are as follows using Passmark CPU Mark AMD Athlon II X2 250uhas secured a score of 980. Intel core-i3 550 has secured a score of 3160.