Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!gistdev!flint From: flint@gistdev.gist.com (Flint Pellett) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Difference between 386/33 & 486/25 not counting fp Message-ID: <1164@gistdev.gist.com> Date: 11 Apr 91 22:48:25 GMT References: <1991Apr7.232112.20682@agate.berkeley.edu> <1163@gistdev.gist.com> <1991Apr9.085749.4568@agate.berkeley.edu> Organization: Global Information Systems Technology Inc., Savoy, IL Lines: 57 >>>In article dd2x+@andrew.cmu.edu (David Eugene Dwiggins) asked: >>>>Is there a significant difference in speed between a cached 33 Mhz system >>>>and a 486/25 system not counting floating point performance? I responded: >>The 486 is a lot faster at everything: generally >2 times as fast, at the same >>clock speed. That means a 25 MHz 486 runs about half again faster than a 33 >>MHz 386. >c60b-1eq@web-1e.berkeley.edu (Noam Mendelson) then stated: >NOT AS FAR AS CPU PERFORMANCE IS CONCERNED. Given the same clock speed, >the 486 runs roughly 50% faster. What you are talking about is a complete >system's performance. This depends on memory, disks, etc., as well as >the CPU. If you perform a CPU benchmark, please post the results. My response, as polite as I can make it: Mr. Mendelson doesn't know what he's talking about: his 50% figure is just plain wrong. Ok, I will post a benchmark, but not mine, this is from Personal Workstation magazine. (Excerpted without permission: I doubt they will mind. If you want to see the full details about the benchmark, I suggest you acquire any copy of this excellent mag, as they post benchmark results every month.) This excerpt shows only one category (DOS) and only 33 MHz machines, and only the Dhrystone tests (they publish results of 5 different tests in 4 different OS'es and about 4 different price categories. Performance ratios between 386 and 486 machines seem to follow the same ratios as the ones below.) DOS 386 Systems: Dhrystone Price Micro Express /33 15,870 $4,998 Laser Ditigal 386/33 15,750 $4,296 Arche Legacy 386/33 17,134 $8,665 Northgate 386/33 17,131 $8,919 AST 486/33 34,192 $4,490 (upgrade board) Club American Hawk III 35,923 $6,495 NCR PC486/MC 33 35,234 $14,995 The Dhrystone numbers drop down to around 12K for the 386 machines at 25 MHz and down to 26K for the 486's at 25 MHz. Unless your arithmetic is different than mine, that works out to about twice as fast, not 50% faster. Yes, these are complete systems being tested: if what you are trying to claim is that factors other than CPU speed are affecting the results of the Dhrystone tests, (since a Dhrystone test does not involve floating point, and does not do I/O) I'd be interested to hear what you think they are, assuming you have some concrete information, not misinformation. (Compiler performance can affect Dhrystone results, but on 386 and 486 machines they are using the same compilers, so that isn't it.) -- Flint Pellett, Global Information Systems Technology, Inc. 1800 Woodfield Drive, Savoy, IL 61874 (217) 352-1165 uunet!gistdev!flint or flint@gistdev.gist.com