FreeArc uses LZMA, PPMD, TrueAudio, Tornado and 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,
multiplies the sum of compression and decompression times with a factor that exponentially grades the ratio of archive sizes achieved by the program under test relative to the best known archive size for that data set.) As of November 2010, FreeArc is the top program in this benchmark, followed by , and WinRAR. It works faster than WinRAR and 7zip.
Like RAR and ZIP it is an archiver. It is not just a data compressor like gzip or bzip2. Initially it supported only its own archive format, normally identified by the
.arc file name extension, incompatible with others; there's no relationship with other .arc formats. More recently, decompression support for other archive types has been added as well, including zip, rar, and 7z. FreeArc has both a command line interface and a GUI. Other features include:
- Solid compression with "smart updates" which avoid recompression when possible
- AES/Blowfish/Twofish/Serpent encryption, including chaining of encryption algorithms
- FAR and Total Commander plugins
- Ability to create self-extracting archives and installers
- Archive protection and recovery layer using Reed-Solomon error correction with user-defined size (for example, recovery over Internet being 0.1%, while default is autosize 1-4%).
Windows binaries are available from the developer. There was no 64-bit version as of January 2012, but may change as the program had not left its alpha stage of development yet.
Linux binaries and source code are not available anymore.