MATSim runs on any machine that has the Java Platform, Standard Edition (SE) 6 or newer installed (commonly referred to as "Java 6" or newer).
Smaller scenarios (e.g. the examples included in the tutorials, 5%- or 10%-samples of large scenarios) can be run on common desktop or laptop computers.
To simulate large scenarios (several hundreds of thousands of agents, networks with ten-thousands of links and nodes), high end computers with a large amount of memory (RAM) may be required to keep the agents' data in memory. The description of agents' plans and the simulation output can take several Gigabytes of hard disk space. To store the data for several scenarios and / or output of simulation runs, large amounts of disk space may thus be needed. MATSim can read and write compressed files to reduce the amount of required disk space, but this aspect still shouldn't be underestimated. MATSim can make use of multiple CPUs or CPU cores that share common memory ("shared memory machine") during the replanning-phase.
Running large scenarios for a high number of iterations can take several hours, up to a few days. Thus it may be advisable to have a dedicated machine running MATSim if you plan to simulate many different scenarios.
The high numbers for free disk space result from the fact that the simulation writes quite a lot of data to the disk during a run. For analysis, usually only the last version of the data is required, and data from earlier iterations can be deleted, freeing space up again.
Currently, we simulate most of our scenarios on machines with 8 or 16 GB RAM, having 2 dual-core processors. The amount of memory allows us to run 2 scenarios at the same time on the machines. A RAID array is used as storage backend, offering about 4 TB of hard disk space. This huge disk space is able to store the results of hundreds of simulations and will suit us for the next few years. Computers and RAID are regular components used in data centers, usually available at moderate prices.