VMD-L Mailing List

From: Axel Kohlmeyer (akohlmey_at_gmail.com)
Date: Sun Oct 02 2011 - 14:34:39 CDT

On Sat, Oct 1, 2011 at 10:20 PM, John Stone <johns_at_ks.uiuc.edu> wrote:
>
> A few minor corrections:
>
> On Sat, Oct 01, 2011 at 08:58:19AM -0400, Axel Kohlmeyer wrote:
> [...]
>> drivers). high-performance quadro cards are very expensive,
>> but most of the features that they offer over geforce
>> cards are not exploited by VMD. so you are probably best
>> off with a GeForce GTX 580 card.
>
> This statement is somewhat inaccurate.  VMD benefits directly
> from the larger memory capacity of the Quadro cards,
> support for stereoscopic display, improved line antialiasing,
> ECC memory, dual DMA copy engines, and other features of the
> Quadro cards.  What Quadro features are you thinking of that
> VMD does not exploit?  For systems with 20 million atoms,

i guess my wording was very sloppy. what i wanted to express
is, that in typical use cases, the performance of a high-end
quadro card is equivalent to a high-end geforce when
using VMD. stereo is a separate issue.

quadro cards are often presented as if they can make
magically stuff faster, but if you are looking at a multi-million
atom system, there is no magic that can give you _that_
much more performance, say with a VDW rep.

> having the larger memory of the Quadro cards is going to be
> a big deal.  The new GPU-accelerated surface representations
> I'm working on will need memory, and this is an area where
> the Quadro has a huge advantage compared with the GeForce cards.

i'm not talking about features that don't exist yet.
and i'd like to note that only the highest-end quadro
cards have a lot more memory than high-end geforce
cards. a quadro 4000 with 256 GPU cores and 2GB RAM
is still significantly more expensive ($750) than a geforce
GTX 580 with 512 cores and 3GB RAM ($550).

however, for a system this large, i'd rather go for
having a dedicated display GPU and then add an
additional dedicated "compute GPU" if possible.
perhaps adding a used Tesla C1060 from somebody
who upgraded to a newer hardware might be a good
deal for that purpose.

the largest issue that i would dmitry expect to run into
is neither GPU or CPU bound but rather a software problem.
he mentioned that he wants to do a cartoon representation
of his huge systems, i fear that this will not go well with
the current STRIDE code. i guess we should add the
necessity of an internal replacement for it to the agenda
for our next meeting.

cheers,
    axel.

> Cheers,
>  John Stone
>  johns_at_ks.uiuc.edu
>
>> cheers,
>>     axel.
>>
>> > Thanks in advance and best regards,
>> > Dmitry Osolodkin
>>
>
> --
> NIH Resource for Macromolecular Modeling and Bioinformatics
> Beckman Institute for Advanced Science and Technology
> University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> http://www.ks.uiuc.edu/~johns/           Phone: 217-244-3349
> http://www.ks.uiuc.edu/Research/vmd/       Fax: 217-244-6078
> 

-- 
Dr. Axel Kohlmeyer
akohlmey_at_gmail.com  http://goo.gl/1wk0
Institute for Computational Molecular Science
Temple University, Philadelphia PA, USA.