Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.advocacy Subject: Re: What to buy??(numbercruncher) Message-ID: <22560@cbmvax.commodore.com> Date: 19 Jun 91 02:00:25 GMT References: <71A0D62DC000263C@FANDM> <1991Jun17.124116.1900@sugar.hackercorp.com> <63@ryptyde.UUCP> <2394@aldebaran.cs.nps.navy.mil> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 46 In article <2394@aldebaran.cs.nps.navy.mil> schweige@taurus.cs.nps.navy.mil (Jeffrey M. Schweiger) writes: >In article <63@ryptyde.UUCP> dant@ryptyde.UUCP (Daniel Tracy) writes: >>Responding to the following: >>"Even the IIfx isn't as fast as a 3000/25." >>That's bull. The IIfx will blow the 3000 away. >Actually, it probably depends on the application. I haven't personally run any comparative benchmarks on the two systems, so I don't really know how a IIfx does against an A3000, all told. I imagine the last statement is true and, in that context, so are the others. For example, disk activity. Without the IIfx using DMA (it didn't in System 6, does it in System 7?), it's going to be significantly slower if it's running full speed SCSI and also attempting to deal with a few CPU bound jobs. With DMA, while the SCSI transfers won't be as fast as the A3000's, there could possibly be more available CPU time if the IIfx has a decent DMA efficiency. >Also, if we're talking about standard configuration machines. If I recall >correctly, the IIfx CPU is rated at 40MHz, but the bus speed is limited to >20MHz. The IIfx has a CPU/cache bus which runs at 40MHz. The main motherboard bus runs at 20MHz, and NuBus of course runs at 10MHz. The A3000/25 runs its main motherboard bus at 25MHz and Zorro III based on 25MHz (Zorro III isn't itself actually clocked, but its strobes are derived from two 25MHz clocks when the 68030 acts as bus master). >This would yield a faster CPU for the Mac IIfx and a faster bus for the >Amiga 3000/25. Well, yes and no. Things that run full speed on the bus will go faster on an A3000 than on a IIfx, but most I/O devices don't necessarily go full speed. Our DMAC does, so it's faster than a IIfx DMAC could be. The 8520s, on the other hand, are pretty slow. Then again, AmigaOS is better able to allocate CPU cycles than MacOS due to its preemptive multitasking. So, bottom line, you don't know. I would wager that the Mac is noticably faster doing a single CPU-bound task, and the A3000 under a heavily disk bound task. Anything else is up for grabs. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "This is my mistake. Let me make it good." -R.E.M.