On Tue, Aug 11, 2015 at 7:01 AM, Suresh A <[email protected]> wrote: > Respected Sir/Friends, > I have formed a PC beowulf cluster (X86_64 old PC's made > on 2007) and installed quantum espresso-5.2.0 in it. Now the cluster is > running very slowly than the single core i5 processor, DDR3 RAM with 1600MHZ > speed. The following is my observation in single core i5 processor and in > beowulf cluster for the titanium dioxide supercell of size 2x2x1. One more > thing is, in cluster every node has 2GB DDR2 RAM with speed 667 MHZ. for i5 > processor 8GB with 1600 HZ. > > total cpu time spent upto now is 408.7 secs (for i5 CPU having > 1600MHZ) > > total cpu time spent upto now is it is keepon running more than 1 hour > (for one single processor in PC cluster) > > total cpu time spent upto now is 1402 secs ( for -ni 10 -nk 10 in PC > cluster) > > > > Is this due to RAM speed, size or anything else?
it is due to *everything*: clock rate, memory speed, memory architecture, processor architecture, processor cache size, disk caching efficiency, availability of SIMD instructions, compiler, libraries. the speed difference you quote seems quite normal for comparing a single core on current hardware versus 8 year old hardware. axel. > > Looking forward to your valuable suggestions > > With Regards, > A.Suresh, > Research Scholar, > Madurai Kamaraj University, > Madurai. > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum -- Dr. Axel Kohlmeyer [email protected] http://goo.gl/1wk0 College of Science & Technology, Temple University, Philadelphia PA, USA International Centre for Theoretical Physics, Trieste. Italy. _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
