It wastes 67 of every 100 clock ticks in a tight loop, doing nothing. Thus, what it does it cut sim speed by 2/3 instead of actually limiting cycles/sec. I'm talking about the button with no graphic that has the erroneous tool tip that says "Limits speed to 15 cycles/sec". What it really does it cut sim speed by 2/3, effectivly using only 1/3 of the available cpu cycles to run the sim.
You are probably simply seeing an artifact of the way cycles/sec are calculated. The tight loop does not process events, preventing the timer event from updating the program's clock. Time slows down (for DB). Thus, while the actual number of cycles per sec drops by 2/3, the displayed and calculated value seems to go up a little because time itself is slowing down a little more than the cycles.
