What is High-Performance Computing?

High-performance Computing (HPC) is the use of specially-designed hardware systems (and associated software) that allow computational operations to be undertaken at higher speed than is possible with "typical" computers.
Typically, HPC systems consist of many individual compute nodes that are connected together in such a way as to make the overall system much faster at computational jobs than any of the individual nodes alone would be. Thus, the combined nodes (dozens, to hundreds or even thousands in number) can work togther to undertake tasks that would take a single node a prohibitively long time.
This relies on not only a large number of compute nodes- the way they pass data between eachother, the way they access common data, and the way the software that is run makes use of the many compute nodes, is of vital importance. So, while an individual node may be no faster than a good contemporary laptop or desktop machine, it is the overall capability of the entire system (multiple compute nodes, their interconnection, data and memory access, and optimised software) that gives the increase in performance.
Such systems are quite complex in terms of hardware, management software and maintenance, and they also require purpose-built rooms with air-conditioning, mains power conditioning and similar non-trivial support infrastructure.
However, without the sort of number-crunching capacity enabled by facilities such as eResearch SA's HPC systems, many of the problems encountered in today's research areas would not be able to be investigated.