Newsgroups: comp.sys.mac.hardware
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!mintaka!mole.gnu.ai.mit.edu!dbert
From: dbert@mole.gnu.ai.mit.edu (Douglas Siebert)
Subject: Re: Comparing the Mac+ and SE
Message-ID: <1991Apr27.191248.29728@mintaka.lcs.mit.edu>
Sender: news@mintaka.lcs.mit.edu
Organization: The Internet
References: <0B010004.a56ymb@outpost.UUCP>
Date: Sat, 27 Apr 91 19:12:48 GMT
Lines: 36

In article <0B010004.a56ymb@outpost.UUCP> peirce@outpost.UUCP writes:
>
>In article <1991Apr26.191830.18589@visix.com>, amanda@visix.com (Amanda Walker) writes:
>> 
>> In article <1991Apr26.153645.5151@rodan.acs.syr.edu>
>> amichiel@rodan.acs.syr.edu (Allen J Michielsen) writes:
>> 
>>    Wrong.  Code in ROM executes SLOWER because of the slow access
>>    times of the roms themselves.  If this weren't the case, you
>>    wouldn't see a drastic system improvement when you copy rom to ram
>>    (and you do, period).
>> 
>> Bzzzzzt.  Thank you for playing.
>> 
>> On the Macintosh Plus and SE (which the original poster was discussing),
>> ROM accesses are indeed faster than RAM accesses.  RAM is time-division
>> multiplexed between the CPU and the video circuitry, while the ROM is
>> not.  Since accessing RAM incurs up to four additional wait states, aggregate
>> ROM execution speed is (on average) from one one and a half to two
>> times faster than RAM, depending on stack and other RAM usage.
>
>This is a PC-ism.  Some PC clone machines do have ROM that is slower
>than their RAM.  But you are right, Macs don't.

I just checked my Mac Plus (4M, rev. 2 ROMs) with Speedometer 2.5, which will
supposedly test a machine against a "standard Mac SE with 20 meg HD"  The
results were (using 1.00 as the SE's score)  CPU 0.82, math 1.02, and disk
6.72 (I used a RAMdisk for the test :) )  The CPU score is pretty much like
most people expected, but the math being a bit faster has me confused...


--
Doug Siebert                    |                dbert@gnu.ai.mit.edu
MBA Student (2nd year)          |  "All opinions expressed herein are obviously
(starting MS in CS this fall?)  |   superior to yours or you wouldn't have need
The University of Iowa          |   to be reading this, now would you?"  :-)