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<p>Hi Nick,</p>
<p> so this is a tricky question. It really depends on your model runs, and what causes you speed limiter.</p>
<p>You will notice that each of these cpus has the same cache and memory bandwidth, but different cache sizes,
<br>
</p>
<p>and cache sizes per core (the E5-2667 has 3.125 MB/core, 8 cores and the <span lang="en-US">
<font face="Calibri,sans-serif" size="2"><span style="font-size:11pt;">E5-2683</span></font></span> has 2.5 M bytes/core 16 cores).</p>
<p>but the<span lang="en-US"><font face="Calibri,sans-serif" size="2"><span style="font-size:11pt;"> E5-2683</span></font></span> has 40 M bytes of cache vs 25 M cache.</p>
<p>So if, when you have divided you domain up into sub domains, 128 sub domains for the 2667s with 400M of cache total,</p>
<p>versus 256 sub domains for the 2683s with 640 M of cache, I expect the extra cache will be very beneficial.</p>
<p>Also the percentage of your domain per M byte of cache is smaller with the 2683s vs the 2667s (100/640 vs 100/400).</p>
<p>So I expect you will get less cache flushing with the 2683s, unless you domains are small and the domain overlap becomes</p>
<p>significant. Also the total compute power in each 2683 is about 30% more.</p>
<p><br>
</p>
<p>For most model runs I expect the 2683's would be faster.</p>
<p><br>
</p>
<p>Russel .<br>
</p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> wrf-users-bounces@ucar.edu <wrf-users-bounces@ucar.edu> on behalf of Witcraft, Nick <nick.witcraft@ncdenr.gov><br>
<b>Sent:</b> Tuesday, 10 May 2016 5:48:10 AM<br>
<b>To:</b> wrf-users@ucar.edu<br>
<b>Subject:</b> [Wrf-users] More cores or faster processors?</font>
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<p class="MsoNormal">Hi,<br>
<br>
We are in the process of building a new cluster, with a total of 8 compute nodes. Would it be better to go with a faster processor with less cores, or a slower processor with more cores?
<br>
Sample options, very similar price:<br>
Intel® Xeon® E5-2667 v4 3.2GHz,25M Cache,9.60GT/s QPI,Turbo,HT,8C/16T (135W) Max Mem 2400MHz
<br>
Intel® Xeon® E5-2683 v4 2.1GHz,40M Cache,9.60GT/s QPI,Turbo,HT,16C/32T (120W) Max Mem 2400MHz<br>
<br>
I did look at Q13 of the FAQ ( <a href="http://www2.mmm.ucar.edu/wrf/users/FAQ_files/FAQ_wrf_installation.html">
http://www2.mmm.ucar.edu/wrf/users/FAQ_ ... ation.html</a> ), but it doesn't really answer this particular question.<br>
<br>
<br>
Thank you,<br>
Nick Witcraft<br>
North Carolina DAQ<o:p></o:p></p>
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<p class="MsoNormal">Nicholas Witcraft, Meteorologist II<o:p></o:p></p>
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