Path: utzoo!attcan!lsuc!maccs!cs4g6ag From: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) Newsgroups: comp.sys.ibm.pc Subject: 386 vs. 486 (was: Re: Brain-dead 286 - summary) Message-ID: <2605244A.12468@maccs.dcss.mcmaster.ca> Date: 19 Mar 90 18:26:18 GMT Reply-To: cs4g6ag@maccs.dcss.mcmaster.ca (Stephen M. Dunn) Organization: McMaster University, Hamilton, Ontario Lines: 30 In article <27842@cup.portal.com> Duel@cup.portal.com (Omid M Farr) writes: $If a 386 runs software made for the 286 (assuming they are at the same clock $rate) at similar speeds, then I take it the 386/486 would follow the same $pattern. No. Intel has heavily optimized the 486, especially in the floating point processor, so that it easily beats a 386 or 386+387 of the same clock speed. $So this is what I think is going on, Please correct me if I am wrong... $A 25 MHz 486 can run software written for the 386 specifically, but a $25 MHz 386 would run the same program at about the same speed, meaning a 486 $really doesn't (today) have any advantages unless you intend on writing $software for it. Well-designed 25 MHz 486 machines have similar or slightly better performance than 33 MHz 386 machines for non-floating point operations, and they outperform a 33 MHz 386+387 combination by a factor of two or better. In the future, some software may be available that has been optimized for the 486's pipelining, which can produce a 15-20% speedup over running 386 software on the 486. However, this is not a consideration now, and personally, I'm not so sure that there will ever be that much software that's aimed specifically at the 486 (but hey, I could be wrong). -- Stephen M. Dunn cs4g6ag@maccs.dcss.mcmaster.ca = "\nI'm only an undergraduate!!!\n"; **************************************************************************** "So sorry, I never meant to break your heart ... but you broke mine."