I would have to guess you are asking why overclocking recedes over time. It does do that. There are plenty of priors why but in short, aging of parts like power supplies, capacitors and more.
It's running at faster than stock so why would anyone call that borke or bad?
Ok my procesor is a core 2 quad q8400
one time i found out it was 75 c ok i replaced thermal paste all good now...Now the problem is i had 2.86 mhz and now i have 2.75 mhz and it dosent go up anymore for some reason is this like the cpu getting weaker or smth or is it mother board broke getting bad and yes i tryed all voltage controls