VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Sun Jan 24 2010 - 13:01:36 CST

Hi,

On Sun, Jan 24, 2010 at 05:57:42PM +0100, Edelmiro Moman wrote:
> Hello,
>
> I am going to buy a HPC to serve both as a graphical workstation and a
> GPU/CPU computing system. The system has two quadcore CPUs and three
> NVIDIA Tesla C1060 GPUs.
>
> As for the graphics card, the retailer is offering a few options:
[...]
> I already have 3 Teslas and thefore there is only room for a single
> graphics card. I am hesitating between NVIDIA GeForce? GTX295 and
> NVIDIA Quadro® FX 3800.

Good to know.

[...]
> I have a few questions:
>
> 1) Does the GTX295 support quad stereo? (I also plan to purchase a
> couple of 3D monitors)

It would for fullscreen games, but not for windowed OpenGL applications
like VMD and similar packages. For this you will need a Quadro.

> 2) Are really the FXs more suitable for interactive rendering in VMD
> (macromolecular surfaces, for instance) or there is really little
> difference between Quadro and GeForce to that respect?

At present, the main interactive rendering differences relate to the
speed and rendering quality for lines and points, for stereoscopic
rendering, and in the amount of GPU memory provided on GeForce
cards vs. on Quadro.

> 3) What about high-quality rendering or movie making?

At present there's not any significant advantage unless you're using
the NVIDIA gelato renderer (supported by VMD 1.8.6 and VMD 1.8.7).

I do plan to try and support the NVIDIA "OptiX" ray tracer one way or
another in a future version of Tachyon and/or VMD, and that too will
benefit from the use of the Quadro cards, but until I actually get
the necessary rendering code written it's not worth worrying about.

> 4) Is it worthy buying the FX3800 or would I be better served with the GTX295?
> 5) Would it be worthy upgrading to a FX4800?
> 6) Is there a better option?

>From my point of view it is primarily a function of how important
stereoscopic rendering is for you since you already have 3 Tesla cards.
If you want VMD in stereo, then you need to go with a Quadro.

If stereo is a low priority item for your needs or it is only needed a
small fraction of the time, my suggestion would be to buy a
GeForce GTX 285 or 295, and buy a Quadro later on when you really
need stereo. If you didn't already have 3 Teslas in this machine,
then another option would be to buy both a Quadro 3800 and a
GeForce GTX 295, and setup both a monoscopic and stereoscopic monitor.
We have a few machines setup this way where we use a top-end GeForce card
to drive a monoscopic 30" 2560x1600 display, and a mid-range Quadro setup
for stereoscopic display. You can buy the GeForce 295 and Quadro 3800
for less than the Quadro 4800 or 5800, so if your stereoscopic needs
are more modest, that might be a reasonable way to go. Keep in mind that
rendering in stereo will already cut your frame rate to half that or less
than monoscopic rendering, so if you expect to be pushing the GPU hard
most of the time, then getting a Quadro 5800 may be your only option.

Best of luck building your new machine.

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078