AMD Athlon II X4 620 Quad Core Processor Review
 

I have to say, I am very impressed with the new Athlon II X4 series processor. This baby performed very well despite having a low L2 cache, no L3 cache and a low clock speed of 2.6GHz. While it was no match for the Intel i7 series, it did come close when put up against the Intel i5 series in the gaming benchmarks and some of the scientific ones as well. When put up against the Phenom II X4 it came even closer, especially in benchmarks where the system as a whole was benchmarked and not just the CPU by itself. When it comes to overclocking, while it will not break any speed records, it did very well considering the multiplier is locked at 13x.

http://www.overclockersclub.com/reviews/athlon2_620/