Module overclocking

What are actual risks of module overclocking?
(Note degraded modules return to non-degraded versions after some time if not further overclocked. Destroyed modules can only be scrapped at the recycler and give the same products as recycling a non-destroyed module would.)
Here's actual table of 6 overclocking levels:
(d = chance for normal module to be degraded;
x = chance for normal module to be destroyed;
dx - chance for degraded module to be destroyed.)

1) Safe. d = 0.2, x = 0, dx = 0;
2) Mostly safe. d = 0.5, x = 0, dx = 0;
3) Unsafe. d = 0.8, x = 0, dx = 0.2;
4) Dangerous. d = 1, x = 0.2, dx = 0.5;
5) Extreme. d = 1, x = 0.6, dx = 1;
6) Burnout. d = 1, x = 1, dx = 1;