alan@oz.nm.paradyne.com (Alan Lovejoy) (02/09/90)
In article <2103@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.com (bill davidsen) writes: > The only comparison which counts is the performance at the highest >production clockrate. When I buy a workstation I don't care about RISC >vs. CISC, or "clock rate efficiency" (there's a marketing term if I ever >heard one), I care about how many clock seconds it takes to run my job. >If the job is CPU bound that maps one to one into CPU sec. Buying the fastest system regardless of clock rate may be a wise move over short time scales. But it may be penny-wise and pound foolish over the long haul. If you are going to commit yourself to an architecture (megabucks for megaboxes), then you care about the ability of the vendor to evolve the performance over time, since you intend to buy the next generation from the same manufacturer when that becomes available. This does not apply to everyone, all the time. But it applies to most purchasers of computer systems, most of the time. Obviously, an MPU that SPECmarks at X at clockrate Y has a much easier time of boosting performance in the next generation than the MPU that SPECmarks at 2X at clockrate 8Y, everything else being equal. But of course, everything else usually is NOT equal, which is what makes life interesting. So, is the 68040 faster than the SPARC at the same clockrate (if it is) because its CISC ISA is superior to the SPARC's ISA? Or is it because the '040 implementation uses more sophisticated wiring? If the latter, then SPARC need only use the 040's implementation strategies to turn the tables on the M680x0 family (assuming they need turning). On the other hand, you may only care which system is the fastest RIGHT NOW, because NOW is when you have to purchase something. Next year you will perhaps buy something else, and port your codes as necessary. If that is the case, MIPS has a box they'd be glad to sell you...for a price. But next week, you'll want to check out what IBM is offering... Unless, of course, you actually depend on other criteria than just current performance for your purchasing decisions? ____"Congress shall have the power to prohibit speech offensive to Congress"____ Alan Lovejoy; alan@pdn; 813-530-2211; AT&T Paradyne: 8550 Ulmerton, Largo, FL. Disclaimer: I do not speak for AT&T Paradyne. They do not speak for me. Mottos: << Many are cold, but few are frozen. >> << Frigido, ergo sum. >>