Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hoptoad!tim From: tim@hoptoad.uucp (Tim Maroney) Newsgroups: comp.sys.mac.hardware Subject: Re: Why 68000? Message-ID: <10223@hoptoad.uucp> Date: 13 Feb 90 22:15:17 GMT References: <1990Feb11.154304.19943@smsc.sony.com> <3919@hub.UUCP> Reply-To: tim@hoptoad.UUCP (Tim Maroney) Organization: Eclectic Software, San Francisco Lines: 36 From article <1990Feb11.154304.19943@smsc.sony.com>, by dce@smsc.sony.com (David Elliott): >> There's been some talk of a new low-cost Mac, which most people >> speculate will use a 68000. In addition, the Mac Portable uses >> the 68000. >> >> What are the advantages of designing a 68000 system over a 68030 >> at this point? I would assume that volume CPU chip cost wouldn't >> be that much more. I wouldn't be so sure; the 68030 is still Motorola's top of the line general purpose microprocessor. Probably at least a factor of four difference in chip price in quantity, conceivably a lot more. In article <3919@hub.UUCP> 6600pete@ucsbuxa.ucsb.edu writes: >I'm no hardware geek, but I do remember reading something about >why the 68000 was used in the portable: power consumption. It was >said that the '030 drew more power by itself than ENTIRE 68000-based >MOTHERBOARD, inlcuding a meg of RAM! I was impressed. This is a bit deceptive. The real comparison here is not between the 68000 and the 68030, but between an nMOS chip and a CMOS chip. The traditional nMOS chips are cheaper to design and fabricate, but they use a lot more power than the CMOS technology. The 68000 in the Mac Portable is a CMOS 68000, not the nMOS 68000 in a Mac Plus or Mac SE. The reason Apple didn't use their current baseline chip, the 68030, in the Portable, is simply that there is no CMOS version of the 030 yet. So, the comparison you draw is probably true, but only if a CMOS 68000 is used; if there were a CMOS 68030, then the power consumption would be in the same ballpark as the CMOS 68000, I believe. -- Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com "It is better to be a human being dissatisfied than a pig satisfied; better to be Socrates dissatisfied than a fool satisfied." -- John Stuart Mill, UTILITARIANISM (1863)