Compressed files are an efficient way to share and send a large volume of documents within a single file, but exactly how much utility are you getting out of the Windows default method of creating ZIP files via Explorer? The ZIP format is old and clunky compared with newer compression methods that create tighter files. However, when choosing a compression format you must also consider what kinds of files you're compressing and who you're compressing the files for.
Compressed Files
- As of October 2011, 7-Zip's default file format -- 7Z -- is considered by several reviewers to be the best compression format for files. Testing of the compression rates for other compression file types, including ZIP, ZIPx and RAR, showed 7-Zip delivers the best compression, with RAR not far behind. While ZIP is the most commonly used compression type, it is outperformed by the other formats. The 7Z format uses LZMA compression by default, but even when using the ZIP format, 7Zip performed significantly better than other compression programs and file types.
Caveats
- Not all compression is alike. Some files, such as documents and uncompressed image files, are easily compressed into very small files. Other files types, such as ISO and compressed image formats, aren't nearly as receptive to compression. In tests that use JPEG files, 7-Zip is actually surpassed by both ZIP and ZIPx. In the case of large, hard-to-compress files, the compression achieved for any file type is negligible -- in some cases less than 10 percent.
Advantages
- Outside the obvious advantage of having the best compression format available, 7-Zip has the benefit of being free, open-source and multi-platform. While the basic 7-Zip program is only available for Windows, 7-Zip is available for Linux and OS X machines in the form of the unofficial package p7zip, available from the 7-Zip website. The 7Z file extension is also decently supported and can be opened by a couple different programs on any operating system, include WinRAR and WinZip. The 7-Zip program also opens and creates other popular compressed file formats, including the ever-popular ZIP and RAR formats.
Disadvantages
- As a file format, 7Z is at a disadvantage because it is still a bit obscure. In a casual setting, the file could potentially confuse whomever you send it to. If they don't have WinZip or WinRAR installed, and instead rely on their explorer's ability to open compressed files, your recipient may not open your file.While compression with 7-Zip is significantly better than the older ZIP format, comparisons do not show a large difference in speed.
