🚀 go-pugleaf

In article <Pine.SV4.3.91.950730155827.2609B-100000@melbourne.DIALix.oz.au> Bernard Morey <bmorey@melbourne.DIALix.oz.au> writes:
>From: Bernard Morey <bmorey@melbourne.DIALix.oz.au>
>Subject: Cheap speed boost
>Date: Sun, 30 Jul 1995 16:03:34 +1000

>This is a report on overclocking using the 'how-to' guide in the
>overclocking FAQ.  I bought a 66.6667Mhz TTL oscillator module from TECS
>(La Trobe St, Melbourne ) for $11.00.  This was to replace the existing
>50.0000Mhz Kyocera oscmod on my 486SX/25 motherboard.  A small roll of
>desoldering braid from Jaycar cost $3. 

>The whole process took two hours, including dismantling the PC and
>removing the motherboard, and re-assembly.  The trickiest part, as I
>expected, was getting the original oscmod off.  
.................................
>I put everything back together and ran Norton Sysinfo.  Bingo -- my PC is>now 
designated a 33Mhz machine.  Old vs new comparison is as follows: 


>Everything runs 20-25% faster.  .........................................
>Bernie

.......................RESPONSE:

What has been described here has a few down sides that have not been explained.

The DMA clock speed is altered by increasing the crystal frequency. This may 
have no effect as some DMA clocks run slow from new but... Norton Utilities 
does not provide evaluation of the DMA clock reports. Over running the DMA 
clock WILL result in premature failure... The board will fry itself.

The second problem is the increased heat generated by a CPU running 25% faster 
than it's rated speed.

As I understand the Chip selection process, slow CPU chips have failed factory 
testing at higher speeds... This is to say all chips have a manufactured 
"speed target". Those that fail say: a 33 Mhz set of tests may see life as a 
25 Mhz chip and those 33s with a faulty FPU might perform as a 25Mhz SX.

Given that the subject crystal was 50 Mhz, the CPU must have been 25 Mhz... A 
chip that the makers considered unsuitable to sell as a 33.

There is no mention either of a heatsink or fan, something I would consider a 
critical addition to such a modification. Apart from these technical and 
possibly future problems; If you are going to upgrade to a faster computer 
anyway and you want to experiment on your old one, that's fine, It'll work for 
a while but you'll end up with needing a new board and CPU as a result so the 
cost in the long run will be higher than if you didn't play around.

My comments should not be read as condeming such experiments after all, we 
will only know more if we keep trying to discover how to know more.
This Sig file is like my tax return... It's still under development,
I have an Engineering student friend helping me with both!