: 64MB to 128MB is usually plenty for documents; higher values require significantly more RAM.
The format (used by 7-Zip ) is widely considered one of the best choices for archiving a "long report" or large document sets because it typically achieves a significantly higher compression ratio than standard ZIP files. Why .7z is "Good" for Reports good.7z
: LZMA2 (best for modern multi-core CPUs). : 64MB to 128MB is usually plenty for