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Date: Mon, 11 Apr 2011 13:09:15 -0500
From: "Kevin Grittner" <Kevin.Grittner@wicourts.gov>
To: <pgsql-performance@postgresql.org>, "Glyn Astill" <glynastill@yahoo.co.uk>
Subject: Re: Linux: more cores = less concurrency.
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Glyn Astill <glynastill@yahoo.co.uk> wrote:
 
> The new server uses 4 x 8 core Xeon X7550 CPUs at 2Ghz
 
Which has hyperthreading.
 
> our current servers are 2 x 4 core Xeon E5320 CPUs at 2Ghz.
 
Which doesn't have hyperthreading.
 
PostgreSQL often performs worse with hyperthreading than without. 
Have you turned HT off on your new machine?  If not, I would start
there.
 
-Kevin