[net.micro] Lisa 68000 speed

bobb (02/01/83)

Last Friday (January 28) at a technical seminar on Lisa architecture, Ken
Fridenburg (?) of Apple said that Lisa uses a 5 MHz CPU for 2 reasons:

    1. The slower processor is obtainable from more sources.

    2. The slower system generates less heat. A fan is not needed,
       leading to a quieter product for office use.

      Bob Bales
      Tektronix

ron@brl-bmd.arpa (02/05/83)

From:      Ron Natalie <ron@brl-bmd.arpa>

Didn't it occur to you that after it took the IBM Series/1 four
minutes that you might have had a bug in your program?  The 68000
has 32 bit registers.  The Series/1 only has 16 bit registers.
Sticking 1000000 into a 16 bit register and then decrementing it forever
yields indeterminate results.   Besides, I don't really think it makes
sense to do such a comparison.  The Series/1 was intended as a multi-user
machine.

-Ron

pal (02/05/83)

The latest BYTE magazine has a review of the Lisa, and they say that the
5MHz clock is used so that the video circuitry has time to refresh the screen
while the processor is NOT accessing memory, leading to a more stable display.