Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!stat!stat.fsu.edu!mccalpin From: mccalpin@masig3.ocean.fsu.edu (John D. McCalpin) Newsgroups: comp.arch Subject: Re: cache speed Message-ID: Date: 18 Aug 89 09:41:10 GMT References: <1473@unocss.UUCP> <3941@phri.UUCP> <1736@crdgw1.crd.ge.com> Sender: news@stat.fsu.edu Organization: Supercomputer Computations Research Institute Lines: 14 In-reply-to: oconnordm@CRD.GE.COM's message of 18 Aug 89 04:23:41 GMT In article <1736@crdgw1.crd.ge.com>, Dennis O'Connor writes: >Summary : it's currently impossible to build a 16-megabyte NMOS, >CMOS, or TTL memory system with a 25ns access time. But with a good >cache design, you can build a system with almost the same performance. Well, it is not exactly 25ns, but each of the 4 cpu's of our ETA-10G at FSU has 32MBytes of 30ns CMOS SRAM. The time required for a load is about 6 cycles, at 7ns/cycle. Deleting the instruction issue time (1-2 cycles?), this is getting awfully close to 30ns. They never could get the 128MByte memory arrays working at 7ns.... -- John D. McCalpin - mccalpin@masig1.ocean.fsu.edu - mccalpin@nu.cs.fsu.edu mccalpin@delocn.udel.edu