From: ray@netcom.com (Ray Fischer)
Subject: Re: x86 ~= 680x0 ??  (How do they compare?)
Organization: Netcom. San Jose, California
Distribution: usa
Lines: 36

dhk@ubbpc.uucp (Dave Kitabjian) writes ...
>I'm sure Intel and Motorola are competing neck-and-neck for 
>crunch-power, but for a given clock speed, how do we rank the
>following (from 1st to 6th):
>  486		68040
>  386		68030
>  286		68020

040 486 030 386 020 286

>While you're at it, where will the following fit into the list:
>  68060
>  Pentium
>  PowerPC

060 fastest, then Pentium, with the first versions of the PowerPC
somewhere in the vicinity.

>And about clock speed:  Does doubling the clock speed double the
>overall processor speed?  And fill in the __'s below:
>  68030 @ __ MHz = 68040 @ __ MHz

No.  Computer speed is only partly dependent of processor/clock speed.
Memory system speed play a large role as does video system speed and
I/O speed.  As processor clock rates go up, the speed of the memory
system becomes the greatest factor in the overall system speed.  If
you have a 50MHz processor, it can be reading another word from memory
every 20ns.  Sure, you can put all 20ns memory in your computer, but
it will cost 10 times as much as the slower 80ns SIMMs.

And roughly, the 68040 is twice as fast at a given clock
speed as is the 68030.

-- 
Ray Fischer                   "Convictions are more dangerous enemies of truth
ray@netcom.com                 than lies."  -- Friedrich Nietzsche
