X-bit Labs reports AMD has admitted that its A-series "Trinity" APUs reduce their clockspeeds during high loads to not let the TDP exceed the default level. This behavior occurs in very rare cases under high loads, and only when Turbo mode is activated.
During the test of AMD Trinity APUs, X-bit labs observed stable drop of clock-speed in Linpack benchmark and irregular drops in various video encoding apps, 3D renderers, etc. It is interesting to noted that the frequency never drops when Turbo Core is disabled and the processor operates at 3.80GHz all the time. As it turns out, in certain cases AMD’s chips deliver lower performance than they are supposed to.
AMD appears to know about the problem and claims that it occurs in very rare cases under loads that are not typical for client microprocessors.