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Date: Tue, 22-Oct-85 01:54:48 EDT
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Posted: Tue Oct 22 01:54:48 1985
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  Subject: Re: all 780s are not created equal
  
  > My real complaint is that two (supposedly) identical systems
  > running identical software take different amounts of time to run the same
  > benchmark.
  
  DEC types will tell you that +/- N% execution speed is to be expected 
  among examples of the same cpu model.  N is around 5-10%.  There might 
  be microcode revisions, etc.  (I would have expected the speed 
  differential to move with the CPU.  Differences in communications and 
  other I/O hardware rev levels might have some impact, though.)
  
  > So I swapped all the CPU boards between the two.  All 16 of them.
  
  Oh, no!
  
  > In a few minutes I will start swapping memory and/or unibus adaptors...
  
  Who handles your insurance?  How much is 10% cpu speed worth in repair 
  bills?  I'm glad there are some gutsy hackers left, but all-in-all I'm 
  just as happy if they don't work for me!
  
  P.S. While you're at it, why not measure the systems with the Fast and 
  Slow clock options?
  
  -Martin Ewing
  
          Caltech (818-356-4970)    PHOBOS::MSE or mse@phobos
          Radio Astronomy 105-24    mse@caltech.bitnet
          Pasadena, CA 91125 USA    mse%phobos@cit-hamlet.arpa