AMD quietly released two additional socket FM1 CPUs that slot in between the Athlon II X4-651 and 631.
The new models 638 (2.7 GHz, 65W) and 641 (2.8 GHz, 100W) integrate 32nm Llano cores with inactive graphics units. AMD is selling both processors for a tray price of $81. In comparison, Intel's cheapest quad-core CPUs are the i5-2390T (2.7 GHz) and the i5-2400s (2.5 GHz) for $184. AMD is riding the value train as $81 buys at Intel just Pentium processors (G850 with two cores and 2.9 GHz for $75, for example).
AMD is offering Athlon II X4 processors also for socket AM3 at 45nm: the 645 (3.1 GHz, 95W, $102) and 640 (3.0 GHz, 95W, $98).