Just remember…there are triggers to CPUs beyond the first one kicking in. Once something has triggered this, those CPUs will continue running for awhile. You will have to watch when CPUs other than than first one are not running, and only then start the program test. The question will remain as to whether the performance jumps at the instant the other CPUs kick in or not.
An alternative is to turn off the idling via information to be found in that other thread, and see if the behavior of performance increase jump goes away.
Activated all cores and set gpu/mem frequency to maximum. I guess I was expecting a bit more from the TK1. I got more or less the same performance than CARMA in single precision, but less in double precision :