[data from a 2.4 GHz Intel Core 2 Duo 6600]

PERFCTR INIT: vendor 0, family 6, model 15, stepping 6, clock 2400116 kHz
PERFCTR INIT: NITER == 64
PERFCTR INIT: loop overhead is 369 cycles
PERFCTR INIT: rdtsc cost is 63.7 cycles (4446 total)
PERFCTR INIT: rdpmc cost is 53.5 cycles (3798 total)
PERFCTR INIT: rdmsr (counter) cost is 219.9 cycles (14445 total)
PERFCTR INIT: rdmsr (evntsel) cost is 190.2 cycles (12546 total)
PERFCTR INIT: wrmsr (counter) cost is 223.7 cycles (14688 total)
PERFCTR INIT: wrmsr (evntsel) cost is 219.9 cycles (14445 total)
PERFCTR INIT: read cr4 cost is 7.3 cycles (837 total)
PERFCTR INIT: write cr4 cost is 113.0 cycles (7605 total)
PERFCTR INIT: write LVTPC cost is 19.2 cycles (1602 total)
PERFCTR INIT: sync_core cost is 215.2 cycles (14148 total)
PERFCTR INIT: read fixed_ctr0 cost is 53.0 cycles (3762 total)
PERFCTR INIT: wrmsr fixed_ctr_ctrl cost is 182.6 cycles (12060 total)
perfctr: driver 2.6.29, cpu type Intel Core 2 at 2400116 kHz