Skip to content

Instantly share code, notes, and snippets.

Show Gist options
  • Save josephb4224/0a1827de36705bc76dbedd77836f9da5 to your computer and use it in GitHub Desktop.
Save josephb4224/0a1827de36705bc76dbedd77836f9da5 to your computer and use it in GitHub Desktop.
Contains descriptions of the various configurable settings used when compressing files in 7-Zip

7-Zip Compression Settings Guide

Archive Format

For the purposes of this document, we will be using 7-Zip's own 7z archive format

Compression level

Dictates the amount the file(s) should be compressed, on a scale from Store (no compression, fastest speed) to Ultra (highest compression, slowest speed).

Compression method

Determines the algorithm to be used in compressing the files. The best algorithm is generally considered to be LZMA2 (Lempel–Ziv–Markov Chain Algorithm version 2).

Dictionary size

Dictates the dictionary size to be used when compressing the files.

Dictionary size Size of Compressed Archive Speed to Create Archive RAM to Compress or Decompress
Small Large Fast Minimal
Moderate Moderate Moderate Moderate
Large Small Slow Maximum

Word size

Dictates the size of "words" to be used when compressing the files. A larger word size results in better compression but causes compression to take longer. The value 64 is typical.

Solid Block size

Dictates the maximum size of a solid block, which is a component of compression useful when storing files of similar size.

Solid Block size (Approx.) Mode Size of Files to be Archived Size of Compressed Archive Speed of Solid Block Extraction Notes
Non-solid N/A Large N/A No solid blocks will be created
Small Small Large Fast Decreased data loss in the event of archive damage
Medium Medium Medium Moderate
Large Large Small Slow Increased data loss in the event of archive damage
Solid Does not matter Variable Variable No limit on solid block size (the blocks may be Non-solid, Small, Medium, or Large)

Number of CPU threads

Dictates the amount of processing power to be used by the computer to compress the files.

Number of CPU threads Archive Size Speed of Compression
Up to 2 Variable Slower
Above 2 May be larger Faster

This guide is still being developed.

Copyright © 2019 Benjamin Zelnick. All Rights Reserved. Permission is granted to non-comercially distribute, modify, and utilize, as long as this copyright notice is preserved and visible on each copy of the document.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment