21.1 What hardware do I need to run modelling programs? (Molecular and Structural Modelling)
Description
This article is from the Chemistry FAQ, by Bruce Hamilton B.Hamilton@irl.cri.nz with numerous contributions by others.
21.1 What hardware do I need to run modelling programs? (Molecular and Structural Modelling)
Supplied by: Dave Young (young@slater.cem.msu.edu)
There are two types of programs that are referred to as molecular
modeling programs. This first is a program which graphically displays
molecular structures as Lewis structures, ball & stick, etc. The second
is a program which does a calculation to tell you something about the
molecule, such as it's energy, dipole moment, spectra, etc.
For an introductory description of various types of computations,
see http://www.cem.msu.edu/~young/topics/contents.html
There are many programs of both sorts available for a large range
of machines. The speed, memory, graphics and disk space on the machine
will determine the size of molecules that can be modelled, how accurate
the model is, and how good the images will look. There are a few programs
that will run on a 286 PC with Windows. There are some fairly nice things
that can be done on a 386 with about 8 MB of RAM and Windows. The
professional computational chemists are generally using work stations and
larger machines.
Currently many computational chemists are using machines made by
Silicon Graphics (SGI) ranging from the $5,000 Indy to the $1,000,000
power challenge machines. These are all running Irix, which is SGI's
adaptation of Unix. SGI is popular for two reasons; first that the power
is very good for the price, second that SGIs run the largest range
of chemical software. However, you will find some computational chemistry
software that can run on almost any machine.
As far as graphics quality, the SGI Onyx (about $250,000) is about
the top of the line. Even if you find a machine that claims to have better
graphics than this, chances are you won't find and chemistry software that
can utilise it.
For chemical calculations there is no limit to the computing
power necessary. There are some calculations that can only be done
on the biggest Crays or massively-parallel machines in the world. There
are also many calculations which are too difficult for any existing
machine and will just have to wait a few years or a few centuries.
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