The following is an excerpt from: Computational biology FAQ, Robert D. Phair, US, 2000 http://www.bioinformaticsservices.com/bis/resources/faq/faq.html
computational biology: The development and application of data - analytical and theoretical methods, mathematical modelling and computational simulation techniques to the study of biological, behavioral, and social systems. ["Bioinformatics at the NIH, 2001] http://grants.nih.gov/grants/bistic/bistic.cfm
I find that people use "computational biology" when discussing that subset of bioinformatics (in the broadest sense) closest to the field of classical general biology. Computational biologists interest themselves more with evolutionary, population and theoretical biology rather than cell and molecular biomedicine. It is inevitable that molecular biology is profoundly important in computational biology, but it is certainly not what computational biology is all about (see next paragraph). In these areas of computational biology it seems that computational biologist's have tended to prefer statistical models for biological phenomena over physico- chemical ones. This is often wise...
One computational biologist (Paul J Schulte) did object to the above and makes the entirely valid point that this definition derives from a popular use of the term, rather than a correct one. Paul works on water flow in plant cells and points out that biological fluid dynamics is a field of computational biology in itself - and this, like any application of computing to biology, can be described as computational biology... Where we disagree, perhaps, is in his conclusion from this---which I reproduce in full: "Computational biology is not a "field", but an "approach" involving the use of computers to study biological processes and hence it is an area as diverse as biology itself."
Richard Durbin, Head of Informatics at the Wellcome Trust Sanger Institute, expressed an interesting opinion on this distinction in an interview on this distinction: "I do not think all biological computing is bioinformatics, e.g. mathematical modelling is not bioinformatics, even when connected with biology- related problems. In my opinion, bioinformatics has to do with management and the subsequent use of biological information, particular genetic information." [Damian Counsell, bioinformatics.org FAQ, 2001]
A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories applicable to molecular biology and areas of computer- based techniques for solving biological problems including manipulation of models and datasets. [MeSH, 1997]