On Tue, 11 Nov 2003, Rod Taylor wrote:
> On Tue, 2003-11-11 at 18:32, Chris Field wrote:
> > We are getting ready to spec out a new machine and are wondering about
> > the wisdom of buying a quad versus a dual processor machine. Seing as
> > how postgres in not a threaded application, and this server will only be
> > used for log/transaction analysis (it will only ever have a few large
> > queries running). Is there any performance to be gained, and if so is
> > it worth the large cost? Any thoughts/experience are much
> > appreciated...
>
> Since you're asking the question, I'll assume you don't have CPU
> intensive queries or monstrous loads.
>
> I'd probably invest in a Quad system with 2 chips in it (2 empty
> sockets) and put the difference in funds into a few extra GB of Ram or
> improved IO.
>
> In 6 months or a year, if you start doing longer or more complex
> queries, toss in the other 2 chips. So long as you don't hit a memory
> limit, it'll be fine.
Note that you want to carefully look at the difference in cost of the
motherboard versus the CPUs. It's often the motherboard that raises the
cost, not the CPUs so much. Although with Xeons, the CPUs are not cheap.
The second issue is that Intel (and AMD probably) only guarantee proper
performance from chips int he same batch, so you may wind up replacing the
two working CPUs with two new ones to go with the other two you'll be
buying, to make sure that they work together.
My guess is that more CPUs aren't gonna help this problem a lot, so look
more at fast RAM and lots of it, as well as a fast I/O subsystem.
2 CPUs should be plenty.
