Dual 64 bit Opteron mainboards are available with 8 DIMM sockets
capable
of taing 16Gb. eg: http://www.tyan.com/products/html/thunderk8w_spec.html
Right, we have one of those (though broken at the moment). Right now, our entire db should fit comfortably in 4 gig of Ram, which we have.
But I totally agree with you about the importance of avoiding the hard drive as much as possible.
--Jimbo
Just to throw my 2 cents-worth into the debate - any particular reason for running on Intel? An Xserve dual G5 gives better price/performance and is (possibly) much easier to administer. It's probably also likely to be more reliable. I'm not an Apple apologist, but I think these machines should be at least given fair consideration. If not, why not?
--Graham