On Tue, Sep 11, 2018 at 5:16 PM Wahab Mirco < mirco.wa...@chemie.tu-freiberg.de> wrote:
> 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), > Depends on the definition of "saturate"; for a typical ~100k membrane protein simulation with h-bonds constraints, already four low-end Xeon cores per GTX 1080 are sufficient to get ~90% of the ~ about peak perf (say what you'd get 2-3x more cores/GPU). With a 1080 Ti and ~4 wimpy Xeon cores, that'll be more around 75-80% of the peak perf. (Side-note: that's with a single run/GPU -- for small inputs like Olga's I'd definitely try to have 2 runs per GPU for efficiency.) Ref: https://goo.gl/8DVqPV Now, considering that the 2700X has 8 _fast_ cores, I'd expect it to work fine with two 1080s (and likely with 1080 Ti's too), though it does depend on the amount of CPU work. > - a larger Threadripper may suffer from memory bandwidth issues on > many parallel threads in Gromacs, > The number of cores will outweigh most bandwidth issues. > - due to AVX2_512, 6C/12T "Coffee Lake" i7 may be somehow faster than > even 8C/16T Ryzen2 (at some scenarios significantly?) > Without a GPU it may, with a GPU it will not. As I said earlier, the benefits of AVX512 are mostly gone with the nonbondeds offloaded to a GPU. > 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) ==> > -- > Gromacs Users mailing list > > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before > posting! > > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists > > * For (un)subscribe requests visit > https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or > send a mail to gmx-users-requ...@gromacs.org. -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.