[gmx-users] Number of Xeon cores per GTX 1080Ti

[Szilárd Páll]

Please don't shift the topic of an existing thread, rather create a
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On Wed, Apr 4, 2018 at 4:01 PM, Raman Preet Singh
<ramanpreetsingh at hotmail.com> wrote:
> Szilard:
>
> Thanks for sharing this valuable info. Very helpful.
>
> We are looking forward to procure a Xeon Phi processor based system. Specs are yet to be finalized.
>
> I am not sure if you have tested Xeon Phi but can you give me insights on the processor. Can I expect the high number of cores to translate into a proportional increase in performance with Phi processor as compared to Xeon E5 series with lesser cores? Can the general estimation "7-10 "core-GHz" per fast Pascal GPU" be applied here too?
>
> I am also concerned that the Pascal GPUs come with 700+ to 3000+ GPU cores.

As a side-note that those are "marketing cores" -- Pascal GPUs come
with up to 30-60 cores (that NVIDIA calls SM's).

> How will the generalization "7-10 "core-GHz" per fast Pascal GPU" change with the number of GPU cores.

Note that this is a *very* rough estimate of resource need for a
balanced hardware setup; the balance can depend more on the simulation
setup than on whether you have 8 or 12 "core-GHz" CPU compute.

GROMACS does offload-based acceleration with GPUs, so whichever
computation (CPU or GPU) is the limiting factor in a certain run will
benefit from more resources. If you have, e.g. a Xeon Gold CPU per
Tesla P100, it's quite likely that the run will be GPU-bound and a
faster GPU will make a large difference. Conversely, if your runs are
severely CPU-bound, faster CPUs will help more.

It is really hard to make an accurate general assessment on how will a
certain CPU-GPU combination perform compared to another. What's
certain is that low-end (e.g. "700 core") GPUs with fast CPUs won't be
very worth it.

--
Szilárd

> Thanks!
>
> Raman
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