"David A. Gatwood said:"
> 
> IIRC, the PAL chip was only necessary (only available) for one particular
> size of memory.  I think that was 4 megs, but I'm probably remembering
> wrong.  Whether it's necessary on the IIx or not, I'm not sure.  I think
> NewerTech or someone has a memory guide that should list those machines.
> Do a web search for memory guide mac, say on google (www.google.com).

I'm pretty sure only the II required PALs; the IIx motherboard was designed
to accept standard 4MB SIMMs.

> AFAIK, no macs require parity SIMMS, but the extra (ninth) bit won't hurt
> anything.

I have been using 9-bit SIMMs in IIx/IIcx/IIci machines for a couple of years
now, with excellent results.  They are frequently cheaper than the Mac-only
SIMMs, due to volume; a pleasant bonus!