The memory on the A64 is really not that much different than an Intel system. Its basically 200 x the multi. The main difference is the LDT which can boost performance, but not much over an LDT of 3 or 4.
A64's also love tight timmings. So if you have some bh-5 or ch-5 laying around I'd use it. OCZ eb is also a very good choice.
As far as the 3.2v for vdimm, that's largely a myth. Most of the A64 deaths were on one mb which had a tendency to spike the vdimm. I've owned 3 A64's and have never run less than 3.3v vdimm and have never had a problem