Compression of large files
Solution 1:
There are versions of bzip (pigz) and bzip2 (pbzip2) which are multi-threaded. Both will use 100% of all cores.
Using the maximum RAM doesn't make sense and the algorithms will take as much as necessary to run, not more.
Which algorithm is best, depends on your use case and data, but pigz will probably be one of the fastest and 7z one of the slowest, but with better compression ratio.