Fabbing 30 pin SIMMs — #21

Post #21 by trag

Source Forum	68kMLA
Category	Troubleshooting
Post Date	Fri, 12 Oct 2012 - 19:18
Original URL	https://68kmla.org/bb/threads/fabbing-30-pin-simms.26286/

Post

(I never got the point of SIMMsavers. Every time I remember upgrading motherboards to one using a newer memory form factor the price of memory had dropped enough it made more financial sense to just buy more new memory than I had in the first place than try to save the old stuff. I can see some edge cases where if you'd *really* broken the bank maxing the memory on the last machine they might save you a few bucks, temporarily, but... factor in the headaches and it's still a stupid idea.)

The one place I've found such a thing useful is the SimmXpander in a Q605. This converts two 72 pin SIMMs to one 72 pin socket.

I've been able to get 260 MB of RAM in the Q605 using one expander and two 128 MB SIMMs. However, thinking about the addressing and architecture of the SIMMs, I can only think of one way it can possibly be working. The Q605 must have four independently operable RAS lines. I thought they were usually paired.