In the "General" tab, set to RAR (Solid mode only works with RAR, not ZIP). Check the box for "Create solid archive" .
Many small, similar files, as it treats them as a single stream to boost compression. Linsh.rar
If you provide this info, I can tell you if you should be using the rar command-line tool or if a simple right-click in Windows will do the trick. rar - ArchWiki In the "General" tab, set to RAR (Solid