OK, how many threads are you exercising? I've written a program that would test Turboboost out by running different numbers of threads, and (me) watching the Turboboost monitor widget. If you have only one thread running, then the max is 3.1 GHz, if you have 2, it's probably 2.8 GHz, and if 4, then 2.6 GHz or so.
If you want the test program, I can probably find and upload it - it's dirt simple.