Path: utzoo!utgpu!news-server.csri.toronto.edu!eecg.toronto.edu!leblanc Newsgroups: comp.sys.amiga.hardware From: leblanc@eecg.toronto.edu (Marcel LeBlanc) Subject: Re: RISC Amiga Message-ID: <1990Nov2.215527.25526@jarvis.csri.toronto.edu> References: <1156@iceman.jcu.oz> <1990Oct30.173846.6928@idt.unit.no> <1990Oct31.012758.26467@jarvis.csri.toronto.edu> <3866.2730b88b@cc.helsinki.fi> Date: 3 Nov 90 02:55:27 GMT Lines: 48 lindblad@cc.helsinki.fi writes: > M. LeBlanc wrote: >> to get the 'cycles per (useful) instruction' as close to 1.0 as possible! >> In fact, the R3000 achieves 1.27 clocks/SPEC integer. You can be sure this >> is better than what the 68040 (certainly the FASTEST of the 68K line) can >> achieve, because Motorola's predicted performance for the 68040 isn't evenb >Current beta (or something like that) versions of 68040 do one istruction >1.3 cycles. And it's instruction set is optimized in a way that mostly used >istructions are fastest. Difference between 1.27 and 1.3 is not worth >mentioning. And by what measurement does Motorola get the claim of 1.3 cycles/instr? This is why I specifically quoted official SPEC numbers for the R3000. NO 68040 workstation vendors have released any SPEC results! None, not ONE! This isn't surprising, because the 68040 isn't officially released yet. If you remember the original article, I wasn't trying to say that the R3000 would have significant speed advantage at equal clock rates, I was just responding to the original poster's claim that "RISCs do virtually nothing with one instruction", which is clearly not true. > Today there are already 30-40 MHz versions of RISC chips. Well, I think >that within months there will be something like 50 or 60 MHz versions of >68040., as there are alredy 50 MHz 68030s and 60 MHz 68882s producted. This doesn't mean anything, since a 50 MHz 68030 isn't even as fast as a 10 MHz R2000. Clock rates don't mean much when cycles/instr are vastly different. 50 MHz 68040 in a few months? We were supposed to be able to buy 25 MHz 68040's almost a year ago. You can buy 40 MHz R3000s today, but you still can't get a 25 MHz 68040. Not that I really care. I'm quite happy with a 68030 Amiga. > I don't think that it would be worth putting RISC chips on Amiga as >CPUs, simply because of differences in instruction sets of 68000-series and >RISC processors. But in future, there will propably be some special purpose >RISC chips on Amiga ... I agree. Let's stick with 680x0's in Amigas for now. >But still most computers to be sold will be CISC computers. For now. Sad, but true. Marcel A. LeBlanc -- Electrical Eng. Computer Group, Univ. of Toronto ----------------------------------------------------------------------- leblanc@eecg.toronto.edu else: uunet!utcsri!eecg!leblanc