On Sun, 2011-12-11 at 16:52 -0500, V G wrote:
> On Sun, Dec 11, 2011 at 4:41 PM, Herbert Graf <hkgraf@gmail.com> wrote:
> > The answer is yes, it does reduce the lifetime of the CPU.
> >
> > There are a few reasons for that, and it varies TREMENDOUSLY on the
> > particular piece of silcon involved.
>=20
> Would you please share some of those reasons?

It depends on the defects. Each piece of silicon has defects. Some are
in places that cause the CPU not to function. Others are in areas where
it doesn't matter, or can be fused around (i.e. for quad core parts, if
one core has a defect that affects it, to save the die, they fuse off
that core and sell the part as a tri-core).

There are also defects that only affect operation above certain
voltages/speeds, so they sell those parts as lower speed rated parts.

Defects also tend to "migrate" over time, this is what will eventually
kill a piece of silicon. Higher voltages and temps cause these to
effects to happen faster (think of pouring sugar into a glass of water,
the sugar will disolve much faster if that water is hot then if it's
cold).

I'm not expert on this, where I work in the chain is well before a chip
gets made, so I'm sure there are other factors that people here will be
able to mention or clarify.

Thanks, TTYL

--=20
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