Conclusion
We looked at four different file archiving solutions and had them compress 650MB of mixed test data. In our first run, we had the programs use their own compression solutions, namely 7z with LZMA2 for 7-Zip, ARC for FreeArc, RAR for WinRAR, and ZIP for WinZip. In a second run, we compared the results using the popular ZIP format, which we believe is most relevant for a majority of users.
Proprietary Formats
The results are pretty interesting. There are severe differences in processing time and significant discrepancies in resulting archive file sizes. At the top of our list: ARC and LZMA/2 deliver the highest compression ratio across our test data when best compression is selected. Unfortunately, ARC and LZMA also take quite a while. If you want really high compression at acceptable processing times, LZMA2 via 7-Zip is best.
ZIP Format
Using ZIP, the resulting archive file sizes did not differ significantly. 7-Zip and WinZip provided the highest compression ratios at best settings. However, the processing time for both was woefully long.
Winners?
If you can freely choose an archiving tool, and if you want to balance compression and processing time, 7-Zip with LZMA2 and WinRAR—both at default compression—deliver the best overall results. For those of you depending on the ZIP format, you’ll want to go with 7-Zip or WinRAR as well, again at default compression. At the best compression setting, you probably aren't going to worry much about processing time anymore. As a result, we don’t recommend any title in particular.
WinRAR and WinZip remain the usability winners. Their feature sets (particularly WinZip’s) are unmatched and provide best experience for less technical users. WinZip offers maximum features, and WinRAR offers a wizard to assist. Enthusiasts and fans of the command line will want to go with 7-Zip and FreeArc.
Losers?
We tried to create a test environment that includes various file types, but it should be possible to squeeze out slightly better results with some of these archiving programs.
However, from a performance standpoint, we can only shake our heads at WinZip’s persistently missing support for threaded operation. It is the only tool here that still only runs on a single processing core at a time when six-core CPUs are becoming available.
