You can now buy PC processors with as many as six cores and support for up to 12 software threads in parallel. With that in mind, why would anyone want the dual-core AMD Phenom II X2 550 Black Edition?
Actually, the theory behind this chip makes reasonable sense. Certain types of software benefit more from high clockspeeds and a big dollop of cache memory than lots of processor cores. Games are one good example. The 550 runs at a healthy 3.1GHz lick and packs 6MB of L3 cache memory. It's also a Black Edition processor and that usually means easy access to even higher clocks. Why pay more for multi-core?
At under £80 the AMD Phenom II X4 550 is certainly affordable. All it needs to do is deliver the goods according to its narrow remit compared to the likes of AMD's Athlon II X4 620, Athlon II X3 435 and perhaps the Phenom II X3 720.