Although the finished cross-compiler is fairly easy on resources,
building it can take a significant amount of processing power and
disk space.
The faster the CPU, the better. The tools and Cygwin can be
very CPU hungry.
The more RAM, the better. Reports are that when building GCC
and GDB, peak memory usage can exceed 256 megabytes.
The more disk space, the better. You need more if you are building
the GNU tools and the amount of disk space for binaries is obviously
directly dependent upon the number of CPUs you have cross toolsets
installed for.
Getting Started with RTEMS for C/C++ Users