I am not saying that DMAC and Ramsey are faulty. It might be the case of CSMKII not playing along nicely with these chips. IIRC, Phase 5 never properly tested it with DMAC4/RAMSEY7 due to the fact that these chips have always been so rare. I think I remember this being discussed yeeears ago on usenet.
It's a theory at least. :-)
BTW, has the CSMKII been confirmed to work in another unit, i.e. A4000 for example?