Zipper, Rar, GZip, BZip2, 7z, Tar, Tar.gz …Īmong the most popular on Windows we have: 7z, Zip and Rar. The first and the second one are free, the latter is not and its developer is the owner (the program that manages this format is WinRar ). To create a zipper file you need to choose an algorithm. The default one used by Windows (for example) is the classic DEFLATE, not very performing. While the program 7z (always for zip creation purposes but with 7z extension) the most efficient LZMA and LZMA2. Rar has been gradually improved over the years and has recently arrived at version Rar5. The default compression is Rar4, you can select version 5 of the compression algorithm by opening the rar file management panel (with the right click on the file to compress>Add to archive).
In general, both Winrar and 7z have a of 30-40% higher performance than that of the simple zip. In addition, Winrar seems to be the only one able to preserve (when unpacking) the original dates of previously compressed folders. The performance of the compression/extraction varies, however, depending on the file that we are going to use, the dictionary chosen, and the machine on which we are operating. With the same factors (therefore changing only the algorithm) from some tests, 7z seems to have a slight advantage (5%) over Rar. Įor starters, Rar5 increases the size of the compression dictionary up to 1GB (in the 64bit version). What this means: the larger the dictionary, which is used to store common parts of a file to be compressed, the better the compression will be, i.e. the less space it will take up once compressed although this only applies to large files (>1GB for backup purposes).
The default size of the Rar compression dictionary is 32MB. In addition, Rar5 also brings the novelty of the ‘restore registry’: Format 5 is much more resistant to damage and loss bits than 4 and is able to reuse even partially corrupted restore data.įinally, with Rar5 it is possible to encrypt data with 256bit AES encryption key algorithm (a very robust key, used for example also by the U.S. Note: files compressed in Rar5 can only be read by WinRar5.
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