How much computer power do I need?
The answer to this question depends upon whether you will be executing the EMS for research or real-time forecasting purposes. For real-time use, you need as much computer power as you can afford, with a premium placed on fast multi-CPU Linux systems with at least 4GB of physical memory. The amount of memory should be commensurate with CPU performance. That's just the nature of NWP, as chances are that you will always want to run the model at higher resolutions over a larger computational domain with the most accurate (and expensive) physics and dynamics. For research purposes you will still want all the best for your runs; however, you will not need to make as many compromises as speed of the machine is not as critical of an issue since you are not up against any deadlines to get a forecast completed. Finally, if you plan on running nested simulations consider increasing the amount of physical memory even further.
The binaries compiled for the EMS should run on any INTEL or AMD Linux (non-BSD) system running a minimum kernel version of 2.6 or later. Also, the processors must support SSE instructions so older AMD and INTEL processors may not be a viable option.
While the minimum amount of physical memory needed is ~2Gb, it is strongly suggested that machines have a minimum of 4 to 8Gb for real-time modeling to avoid paging and swapping issues. In general, if you have less than 4 Gb of memory then consider increasing your system resources. Besides, memory is relatively inexpensive.