The Athlon II X3 455 happens to be one of those processors. On the surface, the X3 455 is only a triple core. However, hiding in the shadows is a sleeping core and cache that has the possibility to be accessed. The X3 455 comes with a stock speed of 3.3GHz. There is a max TDP of 95 watts. In continued AMD fashion, the X3 455 is a 100MHz step up from the X3 450. The Athlon II still remains AM2+/AM3 compatible. Stock settings give 1.5MB of L2 cache."
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips