Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!bagate!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: A3000 fast memory Message-ID: <20914@cbmvax.commodore.com> Date: 24 Apr 91 15:22:00 GMT References: <16200.280c107f@levels.sait.edu.au- <11791@jarthur.Claremont.EDU> <3238@enea.se> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 25 In article <3238@enea.se> tope@enea.se (Tommy Petersson) writes: >What if someone plans to upgrade with a 68040 board? Is it any chance >that faster RAM on the motherboard would be useful? No, the motherboard memory cycle is the same. The limit is the design of the RAMSEY chip, which expects 80ns DRAM and nothing else (well, 90ns DRAM would probably work just fine, but it's not a standard grade). At 25Mhz, the next step down would likely be 50-60ns DRAM, but the RAMSEY device does't know how to adjust for faster memory. The 68040 may, depending on its design, be able to take better advantage of the static column memory in the system. RAMSEY supports burst writes as well as burst reads, though only burst reads are done by the 68030. And while a 68040 bus is a bit easier to interface to than a 68030 bus, both processors run the same minimum burst cycle at 25MHz; it's not like the 68040 can hit memory any faster than the 68030 at the same clock speed. >Tommy Petersson -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "That's me in the corner, that's me in the spotlight" -R.E.M.