Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!uflorida!ufqtp!sutherla From: sutherla@qtp.ufl.edu (Scott Sutherland) Newsgroups: comp.sys.amiga Subject: General question about relative speeds of A2000 and A3000. Message-ID: <1077@orange9.qtp.ufl.edu> Date: 9 Jul 90 19:29:36 GMT Reply-To: sutherla@qtp.ufl.edu (Scott Sutherland) Distribution: na Organization: University of Florida Quantum Theory Project Lines: 53 I am very naive when it comes to the details of the inner workings of computers, so the following question may seem very stupid to some of you. I hope that someone out there can give me an enlightening answer. Here goes. I just got my A3000 last week. It is VERY FAST and I am very pleased with it. I had been looking to upgrade my 2000 with the A2620 or A2630 before the 3000 was announced since I was (and still am) interested in doing faster ray tracing. I read the articles in Amiga World and other magazines (also the latest Amazing Computing). The results show that typical speed increases for the various accelerator boards are from 5-10 times w.r.t. a vanilla 2000. Now, this is QUITE respectible, but I was wondering why the speed increase isn't even greater, especially for math intensive programs like Turbo Silver and SA 3D/4D. Let me explain. (NOTE: This is my understanding of things in very simple terms (that's all I know). I really want someone to help me see where my logic is flawed and to correct my misunderstandings.) The 68000 runs at 7.14 MHz and the 68030 (A3000) runs at 25 MHz. This is a factor of 3.5 faster. The 68000 is 16-bit and the 68030 is 32-bit. This is a factor of 2 faster. Thus, even without a math processor, IN THEORY, the A3000 should be 7 times faster than the A2000. Now, when I purchased an AT&T PC6300 in 1985, I got an 8 MHz 8087 with it. I was told and had read that the speed increases for math intensive programs with this chip would be from 10 to 50 times. So, using this information (right or wrong, this is what I have to work with for my assumptions), the use of a 25 MHz 68882 should, IN THEORY, speed things up AT LEAST as much for the Amiga as my 8 MHz 8087 did for my AT&T (I would think even more, since it is 32-bit and 3 times as fast!). Thus, math intensive programs, ESPECIALLY RAY-TRACING PROGRAMS, should, IN THEORY, run 10-50 times faster with the math chip than without. So, IN TOTAL, with the processor being 7 times faster and the math chip being 10-50 times faster, RAY TRACING programs should run between 70 and 350 times faster on an A3000 than on an A2000, ASSUMING THAT THE CPU AND MATH PROCESSOR SPEED INCREASES OVER THE 2000 ARE MULTIPLICATIVE. Even if they are not, then a 10-50 times increase (should be on the higher end, say 25-50 times) in speed of ray tracing programs should be realized. And the use of 32-bit FAST RAM should make it even faster. So I ask you, why are these math intensive programs only showing a 5-10 times speed increase on a 3000 (or 2630, CSA, Hurricane, etc.) over a stock A2000? Please let me reiterate that this is NOT a complaint of the speed of accelerated Amigas, but a point of naive curiosity. Thanks. Scott Sutherland sutherla@qtp.ufl.edu