Performance in Applications
Video transcoding and non-linear video editing are popular tasks for home users that do require powerful computational resources. And an overclocked six-core CPU would be a great choice in this case.
Final rendering is also one of those well-paralleled tasks. Therefore, Phenom II X6 1055T looks very good here, too. However, it is important to point out that quad-core Core i5-750 overclocked to the same 4.0 GHz can actually compete successfully against the AMD CPU. This is another proof of superiority of contemporary Nehalem microarchitecture that allows executing more commands per clock cycle per core.
Phenom II X6 1055T also copes very well with different types of computational load. For example, no other processors can get even close to it in Folding@Home or during data encryption.
And while in most cases increasing the number of cores is an adequate countermeasure against higher core efficiency, there are also a few examples of the contrary effect. Therefore, many popular applications would run not as fast on the overclocked Phenom II X6 1055T, as you wish they could. And very often six-core AMD CPU would lose even to a dual-core Core i5-660.