7z and RAR are both a compressed archive file format. RAR is a proprietary archive file format and 7z is available as open source. 7z main features are; open (alows any compression or encryption method), high compression ratio with LZMA, strong encryption, large file supports (up to 16 exabytes) an unicode file name. RAR main features are; high compression ratio, strong encryption and recovery record to recover damages archive. Usually the files on the internet are archived using ZIP and RAR, and I seldomly see files archived using the 7z format.

Which have the better compression ratio, RAR or 7z? In this post, I will compare the compression ratio of 7z and RAR.

Program version:
7-zip 4.62
WinRAR 3.80

Winrar

Machine specification:
Windows XP x86
AMD Athlon 64 X2 Dual Core 5000+ 2.6Ghz
3.25GB of RAM (2 x 2GB Mushkin DDR2 PC2-6400)
Sata2 Western Digital 500GB Hard Drive (WDC WD5000AACS)

Test 1: Mozilla Firefox Insallation

Original folder size: 23.9 MB (222 files, 70 folders)
7z: 7.18 MB Time: 14s
RAR: 7.91 MB Time: 14s

Test 2: Video Files
This folder contains MPEG, XViD and x264 videos
Original folder size: 375MB (7 files)
7z: 366MB Time: 272s
RAR: 368MB Time: 242s

Test 3: MP3 Files
This folder contains MP3 files.
Original folder size: 298MB (25 files, 3 folders)
7z: 260MB Time: 248s
RAR: 260MB Time: 166s

Test 4: Text Files
This folder contains TXT and DOC files
Original folder size: 5.4MB (121 files, 71 folders)
7z: 4.28MB Time: 2s
RAR: 4.29MB Time: 2s

Conclusion

7z format is slightly better than RAR when it came to compression ratio. However, the compression time is longer when compared with RAR uses more memory. With modern system, I don't see the problem to use 7z to archive files. If you are looking for the highest compression ratio, you might want to use 7z. If you don't have the time to wait, you can use WinRAR of course. While 7-zip is free and open source, WinRAR is however a 30-day shareware.

[7-zip] [WinRAR]