"scott" <sco### [at] scottcom> wrote in message 
news:4b824ae8$1@news.povray.org...
>> Sometimes parts are sold as 2.8 GHz because they're not stable enough to 
>> run at 3.3 GHz or whatever. And sometimes they're sold as 2.8 because the 
>> 2.8 bin is looking a bit empty this week.
>
> Also don't forget the manufacturer will be testing for absolute worst case 
> conditions, the CPU will only be binned at 3.3 GHz if they think it can 
> survive running at 3.3 GHz (plus a bit) at the maximum specified 
> temperature (plus a bit) for a long time.
>
> They have to do that, because even 0.01% returned unstable CPUs is a huge 
> cost for them - but what this means for the individual user is that 
> they've got a very good chance of being able to overclock the CPU without 
> any reliability issues.
>

I don't know exactly what the manufacturer does, but I would figure that 
they sell a lot more of the 860's than the 870's, simply because there is a 
huge price difference (almost double), and very little performance 
difference between 2.8 and 2.9GHz.  So, even though the CPU may run at 
2.9GHz, they simply don't need to manufacture any more 870's, so it gets 
labeled as an 860.

Anyway...  At stock voltages, I was only able to take it up to 2.9GHz, and 
while it seemed stable, who cares?  I can get way higher than that!  After 
messing around for a couple hours or so, I was able to crank it up to about 
3.8GHz, but it was pretty unstable at that point.  I kept the same voltages 
and lowered it to 3.5GHz, and it seems to be very stable.  I lowered some of 
the voltages and it still seems very stable.  I ran Prime95 on it for about 
an hour and did a couple POV-Ray renders, and no trouble at all.

Apples and oranges, but I had a render that took over 20 hours (POV 3.6) on 
my old computer that ran in under 13 minutes on the new one (overclocked, 
POV 3.7 beta).  The gamma was messed up, though.  I guess I need to read-up 
on how to compensate for that.  Some of the sample scenes ran so fast that 
it didn't even have time to measure the time, and they showed up with a time 
of 0:00.

Suddenly, I'm really starting to feel like rendering again.  Who knew?

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