[gmx-users] Workstation choice

[Wahab Mirco]

On 07.09.2018 20:41, Olga Selyutina wrote:
> ...
> These sets of CPU and GPU are suitable for price (in our region):
> *GPU*
> GTX 1070 ~1700MHz, cuda 1920 - $514
> GTX 1080 ~1700MHz, cuda 2560 - $615
> GTX 1070Ti ~1700MHz, cuda 2432 - $615
> GTX 1080Ti ~1600MHz, cuda 3584 - $930
> 
> *CPU*
> Ryzen 7 2700X - $357
> 4200MHz, 8/16 cores/threads, cache L1/L2/L3 768KB/4MB/16MB, 105W, max.T 85C
> 
> Threadripper 1950X - $930
> 4000MHz, 16/32 cores/threads, cache  L1/L2/L3 1.5/8/32MB, 180W, max.T 68C
> 
> i7 8086K - $515
> 4800MHz, 6/12 cores/threads, cache L2/L3 1.5/12MB, 95W, max.T 100C
> 
> i7 8700K - $442
> 4600MHz, 6/12 cores/threads, cache L2/L3 1.5/12MB, 95W, max.T 100C
> 
> The most suitable combinations CPU+GPU are as follows:
> 1) Ryzen 7 2700X + two GTX 1080 - $1587
> 1.1) Ryzen 7 2700X + one GTX 1080 + one GTX 1080*Ti* - $1900 (maybe?)
> 2) Threadripper 1950X + one GTX 1080Ti - $1860
> 3) i7 8700K + two GTX 1080 - $1672
> 4) Ryzen 7 2700X + three GTX 1070 - $1900
> My suggestions:
> Variant 1 seems to be the most suitable.
> Variant 2 seems to be suitable only if the single simulation is running on
> workstation
> It’s a bit confusing that in synthetic tests/games performance of i7 8700
> is higher than Ryzen 7 2700.
> ...

Sorry for jumping into the thread at this point, but depending on
the problem size and type, it might happen that:

   - a single R2-2700X possibly cannot always saturate TWO
     GTX-1080/1080Ti (maybe Szilárd Páll can add some rule of
     thumb whether and when it can),
   - a larger Threadripper may suffer from memory bandwidth issues on
     many parallel threads in Gromacs,
   - due to AVX2_512, 6C/12T "Coffee Lake" i7 may be somehow faster than
     even 8C/16T Ryzen2 (at some scenarios significantly?)

But it most probably depends on the circumstances. If you want to
spend your money effectively, you have to perform at least some tests.

I can provide some performance numbers I got after updating
Gromacs to v.2018.3 lately on our aging lab hardware.

Regards,

Mirco

==> (I can provide the input file if required) ==>