🚀 go-pugleaf

In <rodthompDCoBDA.6Fr@netcom.com> rodthomp@netcom.com (Roderick
Thompson) writes: 
>
>T&thee (smiteq@gil.ipswichcity.qld.gov.au) wrote:
>: Over running the DMA 
>: clock WILL result in premature failure... The board will fry itself.

Most modern boards allow you to set the DMA clock independently

>: The second problem is the increased heat generated by a CPU running
25% faster 

When you put a heat-sink/fan on them, they run *way* cooler than
factory spec, even if overclocked.

>: As I understand the Chip selection process, slow CPU chips have
failed factory 
>: testing at higher speeds...

Not even close.  Chips marked with a lower speed in most cases were
never tested at higher speeds.  The mfr tests at the speed they need to
fill outstanding orders. If a batch of chips would run at 50, but most
of the orders are for 20, they'll get marked 20.  Recently Intel ran
out of 486sx33's.  So they took a bunch of sx25's, and remarked them. 
The -25 is in the center, the -33 at the bottom.  They sent a letter
saying that these chips were in every way equal to ones that were
marked -33 to begin with.  Of course, we knew that; we'd been running
25's and 33's at 40 MHz for years!  In all that time, we had three
-25's and one -33 that wouldn't clock up to 40 stably.  And we've never
had one fail in the field.  (we're talking hundreds, maybe thousands of
units).


 This is to say all chips have a manufactured 
>: "speed target".

Nope.  They make them, & then see how many pass at the speed they need
to fill existing orders.

>: Those that fail say: a 33 Mhz set of tests may see life as a 
>: 25 Mhz chip

this would apply to a very small # of chips.  The vast majority are
never *tested* at a speed higher than the mark.

Think of the speed mark as a warranty, not as a technical spec.  If it
doesn't pass that speed they'll replace it.


 and those 33s with a faulty FPU might perform as a 25Mhz SX.

Not anymore.  Witness the slaughter of the early Pentiums, which have
been ground to dust.  Why didn't they just mark them as "SX", and sell
them at half price?