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- Path: sparky!uunet!sun-barr!cs.utexas.edu!bcm!aio!heidt
- From: heidt@aio.jsc.nasa.gov (Michael F. Heidt)
- Newsgroups: comp.os.os2.misc
- Subject: Re: Can I mix 70ns SIMMS with 80ns SIMMS
- Message-ID: <1992Jul30.173633.26719@aio.jsc.nasa.gov>
- Date: 30 Jul 1992 17:36:33 GMT
- References: <1992Jul29.174846.11663@tellab5.tellabs.com>
- Organization: NASA Johnson Space Center
- Lines: 20
-
-
- There seems to be a lot of confusion of what the speed rating of RAM
- chips means. An 80ns SIMM is guaranteed to respond to a read request
- with valid data in 80ns. A 70ns will respond in 70ns, etc. If you have
- a very fast computer, it is possible to do the read before the data is
- valid, thus you must be sure that you have the minimum speed SIMM
- required by your computer. The situation can be complicated by things
- like wait states and bank switching, but in general just look at the
- book for your mother board or look at the SIMMs that came in it. You
- can use the same speed OR FASTER (lower access time). Thus 70ns SIMMs
- will work just fine in a machine that works with 80ns or 100ns SIMMs.
- The faster SIMMs will just cost more. We move SIMMs around regularly in
- Intel based machines running MSDOS, OS/2, UNIX etc. with no problems.
- We also do this in SPARCs and SUN4 systems. As long as the SIMMs are
- fast enough they will work. You can't get too fast, just too expensive.
- The tradeoff between 9 chip SIMMs and 3 chip SIMMs is not so clear.
- I would stick with whatever cam in the machine.
-
- Mike Heidt
- heidt@aio.jsc.nasa.gov
-