🚀 go-pugleaf

T&thee (smiteq@gil.ipswichcity.qld.gov.au) wrote:
: 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>
: designated a 33Mhz machine.  Old vs new comparison is as follows: 
: >Everything runs 20-25% faster.  .........................................
: .......................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 
: 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.

Yes, no, maybe ..  Remember we are in a marketing capatilist society
where "truth, justice and the american way" are pawns
of corporate amerika.
eg my Intel 486-sx-25 ran fine for over a year at 33mhz
and the vendor claimed they ran theirs at 40 mhz ok.
Initially, the yield from cpu dies are differentiable by speed
but after awhile they ALL perform well (or fail completely)
but it is up to the marketing department to maximize
profits (econ-1: profits=revenue-cost)
so Intel even sold 486-sx as 20 and 16 mhz !!!
when in reality they would all do 25/33 maybe even 40 mhz...

In fact the first SX chips were actually DX with the FPU
disabled !!!

The DMA clock on most(?) systems runs at 1/2 the ISA bus
speed so one does not wont to go much over 8mhz-ISA-bus
but my AMD (no stinking Intel here) DX2-80 is running
the ISA at 1/4 cpu = 10mhz so the DMA is 5 mhz -  so
far ok bgl;khflfjdjngv;kljnlkgfjl - oops a dma error ????

rod thompson, mailto://rodthomp@netcom.com -----nObOZOSoNtHISbUS-----
sacramento, ca, usa, planet earth          -eVERYtHINGyOUkNOWiSwRONG-