Question Which characteristics should I look for in a computer in order to minimize the run-time for HIFREQ?
Answer The two main components affecting the run-time of HIFREQ are the available RAM and the CPU type and speed. (HIFREQ does a substantial amount of disk activity, but as long as the amount of RAM is sufficient, this activity doesn't add up to a lot of time.)
The amount of available RAM becomes very important for large systems. The amount of memory used by HIFREQ (in MB) is given roughly by 24 * (Nseg / 1000)^2 + 5, where Nseg is the number of conductor segments (after conductor subdivision). For 1000 segments, this is therefore about 30 MB, while for 2000 segments, it is about 100 MB. Should you ever consider running a case with 5000 segments (the current limit), this would require 625 MB. Although Windows can use virtual memory, it is preferable to make sure that the entire memory used by the program is real (i.e. RAM), to minimize disk usage. For reasonable systems (of say <= 2000 segments), 256 MB should be enough. If you plan on modelling larger systems, then you can use the above formula to estimate the memory requirement of HIFREQ, then add about 150 MB for the operating system and other applications.
As for the CPU, the bigger the better. The difference in speed obtained when running HIFREQ on different CPUs depends strongly on the architecture of the CPU and doesn't necessarily follow the clock speed linearly. This means that a 2 GHz CPU can be more than twice as fast as a 1 GHz CPU. The actual speed difference obtained when running HIFREQ will follow pretty much the same trend as that obtained with any other programs, as documented in benchmarks published by PC-Magazine (or similar publications).