Everyone likes to get "something for nothing" and that's just what the new AM3+ motherboards from ASUS and MSI gives AMD enthusiasts just that.
One of the reasons that CPU prices have dropped so dramatically over the past few years is because of product binning. This is a process where products such as CPUs are tested after manufacture and are assigned model numbers based on how well they perform. The best performers are assigned to work at higher speeds than those who didn't perform as well. Not only that, but cores can be disabled in order to improve stability or to fulfill supply chain needs.
In the case of AMD, the Phenom dual and triple core CPUs are, in fact, quad-core parts which have had one or two cores disabled. Better still, some of AMD's latest quad-core CPUs are actually six-core pieces with two cores switched off.
This is where ASUS and MSI come in. The M4-series from ASUS, and the 890GXM-G65 from MSI (both 890GX chipset motherboards) offer a core unlock feature that can allows owners to make use of these hidden cores.
Something for nothing.
Well ... remember that there may well be a reason that AMD disabled a particular core. While these new motherboards can unlock the hidden cores, there's no guarantee that things will work out right. While enthusiasts report good success with core unlocking, look at it as a free bonus, rather than as an entitlement. Remember too, that since AMD locked these cores away in the first place, that you can't expect any support if things go wrong.
Still, these boards give enthusiasts the chance to fiddle about, which is much of the fun!