Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!bpa!cbmvax!daveh From: daveh@cbmvax.UUCP (Dave Haynie) Newsgroups: comp.arch Subject: Re: 80386 vs. 68030 Message-ID: <5375@cbmvax.UUCP> Date: 30 Nov 88 17:30:06 GMT References: <18266@shemp.CS.UCLA.EDU> Organization: Commodore Technology, West Chester, PA Lines: 38 in article <18266@shemp.CS.UCLA.EDU>, kirkaas@oahu.cs.ucla.edu (paul kirkaas) says: > Summary: Which is better? > So, as regards the 80386/68030 -- Which is better? Which is faster? > Why? Going all out, I'd expect a 68020 to be slower than an 80386 system, a 68030 to be faster. The '030 gets a nice boost from internal instruction and data caches and internal split I and D buses. To go full speed, though, an '030 will require faster memory than an 80386 running at the same clock speed, since the '386 with it's pipelining mechanism allows full speed operation most of the time with slower memory. Also, 33MHz versions of the '030 are shipping, while the fastest available '386 is the 25MHz part. > I'm really thinking about the NeXT vs. an 80386 based Unix machine. That's an entirely another question. Market competition in the PClone area has resulted in a whole slew of really good '386 systems, with large external static caches and other performance enhancements. The NeXT machine, according to all the stuff I've read at least, is only a moderate performance 25MHz 68030 system. For instance, the '030 in the NeXT system requires 9 clocks to prefetch a cache line of 4 longwords; the 68030 is capable of doing that in 5 clocks given the proper memory system. On the other hand, the 68030 memory management is supposedly a better match to UNIX than that of the 80386. An intersting test case of this very question is coming up. Sun is supposed to be about ready with a series of '030 based workstations, I guess pretty much an upgrade of the Sun 3 series. Comparing the UNIX performance of one of these to the Sun 386i should be about as equal a test as you can devise. > Paul Kirkaas > kirkaas@cs.ucla.edu -- Dave Haynie "The 32 Bit Guy" Commodore-Amiga "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: D-DAVE H BIX: hazy Amiga -- It's not just a job, it's an obsession