Im not sure. but how "fast" are you talking about? I never have problems opening files and programs... no SSD. Overclocked but will throttle down to 1600mhz when my CPU is not in load.... How are you sure that the CPU is running at 1600mhz for that "split second" you are opening a program? Could it be possible that the CPU immediately returns to full overclock frequency for the milliseconds it needs the CPU to do an operation... then goes back to 1600mhz (but you do not see it as it happens so fast so you think you are at 1600mhz all the time).
Ive never had a problem with my CPU going down to 1600mhz at idle. your OC should be stable to begin with...if youre crashing in games and getting instability with an overclock in the first place; shouldnt that be the source of your problems?