[Wien] Hardware (i7-7700k?) for WIEN2k

Tue Sep 19 08:36:15 CEST 2017

Without knowing the new i7-7700K myself, a few recommendations:

You do NOT need more memory than 64 GB (in fact we have at most 32 GB on 
our  workstations). If a calculation requires that much memory, the 
single processor speed is too slow anyway.

I'd go for the I7, because it has faster memory and faster clock speed.

The advantage of a Xeon is usually that that you can combine 2-4 CPUs on 
a single motherboard. But usually have pay a lot for this possibility.

PS: I'd certainly also get in addition a regular 2-4TB harddisk (costs 
nothing, but is very useful)

Peter Blaha

On 09/19/2017 06:20 AM, Gavin Abo wrote:
> Some additional comments:
>
> If you need an idea of about how computational intensive a WIEN2k
> calculation might be for around 60 atoms per cell or more.  The links
> below and links in those posts might be helpful:
>
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14035.html
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg01420.html
> https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg05784.html
>
> The hardware specifications for the i7-7700K and E5-2623 v3 processors
> should be at the links:
>
> https://ark.intel.com/products/97129/Intel-Core-i7-7700K-Processor-8M-Cache-up-to-4_50-GHz
> http://ark.intel.com/products/83354/Intel-Xeon-Processor-E5-2623-v3-10M-Cache-3_00-GHz
>
> The specifications look fairly similar.  So maybe there would not be too
> much of a difference in the WIEN2k calculation run times between the two.
>
> The i7-7700K supports a Max Memory Size of 64 GB.  The E5-2623 v3 could
> have a major advantage when it comes to supporting a Max Memory Size of
> 768 GB.  However, if the motherboard the E5-2623 v3 goes on does not
> have memory expansion slots for more than 64 GB or if you never plan to
> add additional memory modules to increase the memory beyond 64 GB, then
> that would not matter.
>
> The i7-7700K does have about a 1 GHz faster processor frequency and it
> looks like it supports a faster RAM (DDR4-2133/2400, while the E5-2623
> v3 supports a slower DDR4 with frequency of 1600 or 1866 MHz).  So this
> might give it better performance than the i7-7700K if the calculation
> uses less than 64 GB of RAM.  Above 64 GB, the workstation would likely
> use virtual memory and disk caching may significantly slow a calculation
> (whereas the E5-2623 v3 with more than 64 GB should extend the limit of
> this RAM bottleneck).  The i7-7700K also supports DDR3L-1333/1600.  If
> both the i7-7700K and E5-2623 v3 workstations happen to use the same
> DDR3 1600 RAM, then no speed up or slow down is expected from the RAM
> frequency.
>
> More importantly than all that may be the launch date for the E5-2623 v3
> of Q3'14, while Q1'17 for the i7-7700K.  The Xeon E5-2623 v3 has been
> around awhile.  So Linux distributions most likely have drivers that
> support this processor.  With the i7-7700K being so new, you might have
> to be more cautious.  If you decide to get the i7-7700K, I recommend
> checking that the Linux distribution, compiler (in particular if you
> plan to use a non-Intel compiler like gfortran), and libraries (such as
> a blas library with the non-Intel compiler) that you will be using are
> able to support and recognize the processor.
>
> As an example, I think it was the Intel HD Graphics 530 onboard the
> Intel Skylake processors when they were first launched that didn't have
> a good Linux driver [
> https://askubuntu.com/questions/698168/cant-get-intel-hd-graphics-530-skylake-i7-6700-to-work
> ]. If I recall correctly, the graphics were broken (or of poor quality)
> for several months until the drivers were finally released.
>
> Of note, there is also seems to be a E5-2623 v4:
>
> http://ark.intel.com/products/92980/Intel-Xeon-Processor-E5-2623-v4-10M-Cache-2_60-GHz
>
> On 9/18/2017 6:54 PM, Yundi Quan wrote:
>> hi,
>>
>> 4 cores with 8 threads is probably OK for using WIEN2k to study
>> transition metal oxides. For post-processing tools, such as
>> wien2wannier, it requires more memory. But 64 GB is enough in most
>> cases. I once bought a Dell XPS with 4 cores and 8 threads, 16 GB
>> memory back in 2011. It worked well for most of my calculations. Hope
>> this helps.
>>
>>
>>
>>
>> On Mon, Sep 18, 2017 at 2:44 PM, Karsten Küpper <kkuepper at uos.de
>> <mailto:kkuepper at uos.de>> wrote:
>>
>>     Dear WIEN2k-community,
>>
>>     We want to buy a workstation dedicated to run WIEN2k.
>>     Our aim is to calculate mostly transition metal oxides with unit
>>     cells ranging from 24 - 128 atoms supercells.
>>     We are thinking about a workstation with at least 4 cores, at
>>     least 64 GB RAM, and a 1TB SSD as a starting point.
>>
>>     1) May that be a reasonable choice?
>>
>>     2) Has anybody experiences with the i7-7700K 4.2 GHz (maybe also
>>     compared to Intel-Xeon E5-2623 processors),  as there is no
>>     benchmark test available on the WIEN2k homepage by now.
>>
>>     Thanks for your efforts in advance!
>>
>>     Kind regards
>>     Karsten Küpper
>>
>
>
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
WWW:   http://www.imc.tuwien.ac.at/TC_Blaha
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