AMD Phenom II X4 940 Overclocking With Various Motherboards
 

Even these results get it borne in that it's much easier to choose a motherboard for overclocked Phenom II than for Phenom. Yep, it sounds very strange, as we managed to overclock our sample to impressive 3800MHz, and it's not even the best result for Phenom II, as you may read in overclockers' forums. The first explanation that comes to our mind is significantly reduced power consumption. By the way, Phenom processors (B3 revision) have no real problems with their power consumption at nominal frequencies either. But when overclocked, a motherboard must really supply high currents (in tests and programs with high CPU load). And preserving stability in these conditions is precarious at best. To keep the system stable, VRM must be cooled well. Besides, design peculiarities also make themselves felt, hence different overclocking results of various motherboards.
http://ixbtlabs.com/articles3/cpu/ph...ocking-p1.html