FreeArc

FreeArc is a free and open source file archiver developed by Bulat Ziganshin. As of H1 2017 FreeArc Next, which is a native 64-bit archiver rewritten from scratch and include Zstandard support, is under heavy development.

FreeArc uses LZMA, Prediction by partial matching, TrueAudio, Tornado and GRzip algorithms with automatic switching by file type. Additionally, it uses filters to further improve compression, including REP (finds repetitions at the distances up to 1gb), DICT (dictionary replacements for texts), DELTA (improves compression of tables in binary data), BCJ (executables preproccesor) and LZP (removes repetitions in texts).

In a 2010 Tom's Hardware benchmarks comparing it to the other popular archivers WinZip, 7-Zip, and WinRAR, FreeArc narrowly outperformed them by small margin in its "best compression" mode, but lost to 7-Zip's LZMA2 in the "default compression" tests, still compressing better than WinRAR and WinZip at this setting.

In the same Tom's Hardware tests, FreeArc was outpaced at default settings by 7zip's LZMA2 default compression, and also by WinRAR, even at its best compression settings. FreeArc's compression at its best settings was slower than both 7zip and WinRAR, but still came ahead of WinZip.

In a metric devised by Werner Bergmans of Maximum Compression Benchmark, FreeArc compression is more efficient than programs for classic formats like .Z (LZW), .zip (Deflate), .gz or bzip2. (The scoring formula used in this non-public test,