VMD-L Mailing List

From: Robert Brunner (rbrunner_at_illinois.edu)
Date: Mon Nov 17 2008 - 14:42:45 CST

VMD makes use of standard OS "virtual memory". However, if you're
using one of the pre-compiled Windows binaries, It is compiled as a 32-
bit program, and therefore can only access 2G of real or virtual
memory, I think. I'm not sure whether you can compile the latest alpha
source to get a 64-bit binary, but even if you can access more than 2G
of memory, performance will be poor unless you can fit all of your
data into actual RAM.

If you're asking whether it takes advantage of some kind of program-
specific disk file for out-of-core processing of trajectory data, no
it does not. Everything is loaded into the program's address space.

On Nov 17, 2008, at 11:48 AM, tinifcarter_at_gmail.com wrote:

> Hi,
>
> I have a general question regarding the memory use of VMD here.
> In windows, is VMD capable of using the virtual memory or is it
> capable of storing large data file temporarily in harddisk? I am
> using VMD for the visualization of large configurations (200000
> atoms in each frame, usually more than 500 frames in total) and I
> just have 4GB RAM on my desktop, so it would be a bad news for me if
> VMD can't use virtual memory.
>
> Thanks,
>
> Shuai