On Thu, Apr 2, 2015 at 6:33 AM, Pietro Pugni <pietro.pu...@gmail.com> wrote:


> *T420*
> work_mem = 512MB
>


> *MacMini*
> work_mem = 32MB
>

So that is why the T420 does memory sorts and the mini does disk sorts.

I'd start looking at why memory sorts on the T420 is so slow.   Check your
numa settings, etc (as already mentioned).

For a drastic test, disable the 2nd socket on the dell, and just use one
(eliminate any numa/QPI costs) and see how it compares to the no-numa
MacMini.

If you want to see how bad the NUMA/QPI is, play with stream to benchmark
memory performance.

a.

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