From: rvenkate@ux4.cso.uiuc.edu (Ravikuma Venkateswar)
Subject: Re: x86 ~= 680x0 ?? (How do they compare?)
Distribution: usa
Organization: University of Illinois at Urbana
Lines: 59

ray@netcom.com (Ray Fischer) writes:

>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

How about some numbers here? Some kind of benchmark?
If you want, let me start it - 486DX2-66 - 32 SPECint92, 16 SPECfp92 .

>>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.

Numbers? Pentium @66MHz - 65 SPECint92, 57 SPECfp92 .
	 PowerPC @66MHz - 50 SPECint92, 80 SPECfp92 . (Note this is the 601)
        (Alpha @150MHz  - 74 SPECint92,126 SPECfp92 - just for comparison)

>>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.

Not in a clock-doubled system. There isn't a doubling in performance, but
it _is_ quite significant. Maybe about a 70% increase in performance.

Besides, for 0 wait state performance, you'd need a cache anyway. I mean,
who uses a processor that runs at the speed of 80ns SIMMs? Note that this
memory speed corresponds to a clock speed of 12.5 MHz.

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

Numbers?

>-- 
>Ray Fischer                   "Convictions are more dangerous enemies of truth
>ray@netcom.com                 than lies."  -- Friedrich Nietzsche
-- 
Ravikumar Venkateswar
rvenkate@uiuc.edu

A pun is a no' blessed form of whit.
