Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!isc-br!hawk!wddami!wayned From: wayned@wddami.spoami.com (Wayne Diener) Newsgroups: comp.sys.amiga.hardware Subject: Re: RISC Amiga Message-ID: Date: 31 Oct 90 23:23:52 GMT References: <1990Oct30.192213.12708@Neon.Stanford.EDU> <2425@trlluna.trl.oz> Sender: uueagle@hawk.isc-br.com (Eagle Proj UUCP login) Lines: 33 >In article <2425@trlluna.trl.oz> aduncan@rhea.trl.oz (Allan Duncan) writes: >From article <1990Oct30.192213.12708@Neon.Stanford.EDU>, by torrie@Neon.Stanford.EDU (Evan James Torrie): >>>On the other hand, the 68040 is as fast as current-generation RISC >>>chips. So why go RISC at all? >> >> Because next year's implementation of RISC (the 88110) will be about >> two to three times faster than next year's implementation of the 68040 >> (even with the 040 running at 50MHz) > >When you configure in memory at prices we in the street can afford (ie >dynamic ram) riscs stop dead, as their high mip speed is derived from >memory fetching on every cycle, whereas a cisc spends some time decoding Well, not exactly. If you're talking about high performance systems and are willing to grant that they'll need a fair amount of memory, it's fairly easy and inexpensive to go to, say, 4 way interleaving on the memory, use slower RAM chips than we're trying to stick in our machines right now and still decrease the actual memory cycle time. Four megabytes, consisting of 16 256K simms would cost less than $500, and using even 120 NS parts would yield an effective access time of 30 NS. Using 16 1 MB simms would give a 16 MB memory module for less than $1500. Same sort of timing calculations. The problems arise in any memory expansion. If you start out at the four MB level, then that's also your expansion increment. -- |---------------------------------------------------------------| | // Wayne D. Diener | | // Spokane, WA | | \\ // E-mail reply to: | | \X/ To: isc-br!hawk!wddami!wayned@uunet.uu.net | |---------------------------------------------------------------|