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Home Forums 68kMLA Mac II (and IIx) RAM limits — #1
Post #1 by zuiko21
Source Forum68kMLA
Category68k
Post DateTue, 29 Nov 2011 - 22:22
Original URLhttps://68kmla.org/bb/threads/mac-ii-and-iix-ram-limits.24310/
Post
Hi all!

After researching a bit, I'm still a bit confused about the subject... it's clear that both machines will work fine with 8 MB (eight 1 MB SIMMs) and that MODE32 is required in order to recognize larger amounts (32 bit addressing). But:

•My II is pretty stock -- no PMMU (has the Apple kludge instead), standard ROMs (no FDHD). Does it really need the 68851 PMMU for anything over 8 MB? Is the Bank A limited to smaller SIMMs than Bank B?

•My IIx booted fine with four 2 MB sticks, but were detected as 1 MB only :( Those very same SIMMs make Death Chimes on the SE/30... Will regular 4 (or 16!) MB SIMMs do?

What's a PAL SIMM anyway? My 2 MB SIMMs do have a (PAL?)16L8 chip and four 514400 DRAM chips. They work fine on the Colour Classic, though.

Thanks a lot in advance!

mp.ls