[comp.sys.mac.hardware] SIMMs of differnt speeds in IIsi

jnowak@magnus.acs.ohio-state.edu (Joe Nowak) (06/17/91)

I have (4) SIMMs that were originally in a Mac Plus that I'd like to put
in a Mac IIsi.  (2) are 100ns chips and (2) are 80 ns chips.  In the Plus
the different speed chips were in different SIMM banks.                          
My question is, is there a problem with chips of two different speeds residing
in the same SIMM bank of a IIsi?  (or a II, IIx, IIcx or SE/30 which also
have 4 SIMMs per bank and can use 100ns SIMMs).

Bank A of the IIsi is the 1 MB soldered on the board and Bank B consists 
of 4 SIMM slots.  The Apple literature says the IIsi can take 100ns chips
no problem but I am want to know if mixing SIMM speeds in the same bank 
will cause troubles.  

Response here or by email is fine.  Thanks in advance.

amanda@visix.com (Amanda Walker) (06/18/91)

jnowak@magnus.acs.ohio-state.edu (Joe Nowak) writes:

   The Apple literature says the IIsi can take 100ns chips
   no problem but I am want to know if mixing SIMM speeds in the same bank 
   will cause troubles.  

All four SIMMs must be the same size.

Each SIMM individually must be as fast or faster than the slowest speed
rated for the machine (100ns, in this case).  The SIMMs do not need to
match each other.

Maybe we should start a regular Frequently Asked Questions posting.
We went through a flamewar about this a few months ago, and I really
don't want to go through it again...

It works.  Apple engineers say it works.  I've *done* it, and it works.

Don't worry, be happy :).

--
Amanda Walker						      amanda@visix.com
Visix Software Inc.					...!uunet!visix!amanda
-- 
"I'm not a vegetarian because I love animals; I'm a vegetarian because I hate
 plants."	--A. Whitney Brown

ccjapu@uta.fi (Jarmo Puntanen) (06/18/91)

Mixing RAM speeds within the same bank or otherwise does not hurt, 
as long as all chips meet the minimum speed for that machine type.