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Re: 68040 clock doubling



No. As I understand it, Apple's marketing department decided to response
to what had been standard practice in the WinTel world; that is, quoting
the processor speed, rather than the bus speed. Apple had been using the
more conservative rating, but decided to change to what had become an
industry standard method of quoting speed. Thus, consumers that had been
comparing, say, a 33mhz 68040 to a 66mhz 80486 and concluding that the 486
was faster & therefor better ('taint so,) would be more inclined to
compare Apples & oh, say, prunes and thus arrive at a more enlightened
conclusion.

Here's a quote from the Executor FAQ.

" Question 1.8. How fast is Executor? 

Executor converts mc680x0 instructions into 80x86 instructions and then
runs the new instructions. There is some overhead associated with this
process, but for cpu intensive tasks, a 75 MHz 486DX4 will run
approximately as quickly as a 25 MHz 68040. NOTE: Lately some people have
begun calling 25 MHz 68040s "50 MHz 68040s", but we're not using that
trickery in our description. The paper /pub/SynPaper available on
ftp.ardi.com describes how we can run mc68040 code so quickly on an 80x86.
SynPaper compares a few different systems and shows that a 90 MHz Pentium
runs almost as fast as a 50 MHz 68040. "



In article <edkemp-1602961304180001@ekemp.consult.csc.com>,
edkemp@tiac.net (Eric Kemp) wrote:

-> > 
-> > Now, when Apple decided to start calling its, for example, powerbooks
-> > "33/66-MHz" PowerBooks, I just had to laugh. This shows just how
-> > desparate they are. The 68040 does indeed use two different clocks signals.
-> > This is an implementation choice that does not necessarily have
-> > anything to do with exactly how the internal processor core operates.
-> 
-> While I agree that this is misleading, I believe it was done to indicate
-> the clock speed if the machine is upgraded to a PowerPC chip.  The Quadra
-> is used to own was 33 Mhz base, 66Mhz with upgrade.  I would not call this
-> an act desperation.  Unfortunately, the general public views megahertz as
-> the ubiquitous definition of speed (like MPH) when it is accurate only in
-> comparison to the same processor.


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