> 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. I agree that the additional cpus won't help as much since I haven't found any benefits in terms of individual query speed for a quad vs. an smp on benchmarks I've run on test machines I was considering purchasing. Quads are also expensive - on similar architectures the quad was 20k vs 7k for the dual. > > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED]) >
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