FreeArc uses LZMA, PPMD, TrueAudio, Tornado and GRzip algorithms with automatic switching by file type, and also uses set of filters—for instance it can remove repetitions from text.
In 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.
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 NanoZip, bsc 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