----------------------------Original message----------------------------
On Wed, 23 Mar 1994 11:59:54 EST DEBBIE LORDS said:
>----------------------------Original message----------------------------
>     Don't be fooled by the claim of a fast 66 mhz machine.  A 50 mhz
>actually runs faster.
>     Now that I have your attention.  According to a magazine article I
>recently read (last month), the 66 mhz machine runs at 66 for internal
>processing only, like doing a dir or a cd.  But is that important?  After
>all, how fast can you read a whizzing directory listing?  (And do you want
>to?)
>     When it comes to the workhorse needs, like data i/o, the machine runs at
>a whopping 33 mhz.  Great.  And we all know that what we are interested it is
>using DATA, some of it intensely slow for slower machines.
>
>     A 50 mhz machine runs at 50 for everything.
 
Actually, this is about 30% right.  And 70% wrong.  Most IO will occur at bus
speed, which in a traditional PC architecture is limited by disk geometry.
And if it were not so limited, it would be limited by bus speed, which is a LOT
lower than 33Mhz for most 50Mhz ISA and EISA machines.
 
This is a complicated issue (bottleneck analysis) and if you want to under-
stand it, don't expect a half hour read of some PC mag to help much.  Most
such authors don't understand the issues either.   Nobody on the PC side of
the house seems to want to spend the effort ($$$) to figure out what is
going on, but a few hours by a good consultant will clarify things.   Dave
 
Dave Gomberg, role model for those who don't ask much in their fantasy lives.
GOMBERG@UCSFVM           Internet node UCSFVM.UCSF.EDU     fax-> (415)731-7797
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