Compression ratio results are very dependent upon the data used for the tests. We compared 7-Zip with some of the leading commercial archivers: PKZIP 2.04g, WinZip 7.0.
FILE SET: The Canterbury Corpus (11 files totaling 2,810,784 bytes, popular file set used to compression rates).
| Archiver | Compressed size | Ratio |
|---|---|---|
| 7-Zip (zip format) | 676284 | 100% |
| PKZIP 2.04g -ex | 726047 | 107% |
| WinZip 7.0 (Max) | 731499 | 108% |
7z is the new archive format, providing high compression ratio.
FILE SET: The GIMP 1.2.4 for Windows after full installation (127 subfolders, 1304 files totaling 27,128,826 bytes). The GIMP is the GNU Image Manipulation Program. It can be downloaded from www.gimp.org.
| Archiver | Compressed size | Ratio |
|---|---|---|
| 7-Zip (7z format) | 5445402 | 100% |
| WinRAR 3.10 | 6004155 | 110% |
| WinAce 2.3 | 6242424 | 115% |
| CABARC 1.0 | 6455327 | 119% |
| 7-Zip (zip format) | 9461621 | 174% |
| PKZIP 2.50 | 9842800 | 181% |
7-Zip provides best compression ratio for GZIP format. Compression ratio is equal to compression ratio provided for ZIP format.
7-Zip provides superior decompression speed for RAR archives.
For solid archives it decompresses only files
needed for decompressing. For example,
there is solid archive archive.rar (containg 100000 files)
that was created with command:
rar a archive.rar -s100 * -r
In that solid archive each 100 files are compressed as one big file.
And if you try to extract one file from that archive,
7-Zip will decompress (in memory) only
from 1 to 99 files. So you will have advantages
of solid compression and big speed.