* Steve Wolfe (nw@codon.com) wrote:
> The main question in my mind is whether a 4-way Opteron is going to
> give me enough of a performance benefit over a 2-way Opteron to make the
> extra $10k worth it. My first guess was that it would, as going from 2
> Opterons to 4 will give you twice the potential memory bandwidth.
> However, as PostgreSQL pulls heavily from the global buffers, I may not be
> able to utilize all of that potential bandwidth.
Well, one question to ask, of course, is how much overlap is there in
the queries? I think that'd make some difference... Besides that, make
sure you get enough DIMMS (2 per CPU) to get interleaved memory access
going on the Opterons. I'm guessing you realize this already, but
figured I'd mention it anyway. :) When I got my opterons in I hadn't
realized it'd do interleaved till I was flipping through the MB manual.
:)
Stephen