Freearc
Free, open-source, with console and GUI versions for both Windows and Linux
WinXP, Vista And Win 7 32 and 64bit

FreeArc is a modern general-purpose archiver. Main advantage of FreeArc is fast but efficient compression and rich set of features.

FreeArc works 2–5 times faster than best other compression programs.

Free, open-source, with console and GUI versions for both Windows and Linux
Includes LZMA, PPMD, TrueAudio and generic Multimedia compression algorithms with automatic switching by file type
Filters that further improve compression: REP (finds repetitions at the distances up to 1gb), DICT (dictionary replacements for texts), DELTA (improves compression of tables in binary data), BCJ (executables preproccesor) and LZP (removes repetitions in texts)
Special compression algorithms are used in fast compression modes (GRZIP for texts and Tornado for binary data)
Overall, 11 compression algorithms and filters are included (compared to 3 in 7-zip and 7 in RAR) and this number still grows
Smart file sorting that groups similar files together and fully customizable sorting order (see below) further improve compression
Typically, FreeArc works 2-5 times faster than best programs in each compression class (ccm, 7-zip, rar, uharc -mz, pkzip) while retaining the same compression ratio; from technical grounds, it’s superior to any existing practical compressor
Moreover, you can use any external program as compressor or filter as easy as internal ones, with Precomp, ECM, CCM(x), PPMonstr, Durilca, LPAQ, UDA and PAQ are already preconfigured in arc.ini as shipped
You can fine-tune settings for each compression algorithm, and which compression algorithms are used for each type of files; you can create new compression profiles and modify existing ones; use -dic$ option in order to see all details of compression used

Features

Solid compression with smart updates (only changed solid blocks are recompressed)
User-definable solid block size (-s…) and file sorting order (-ds…), including customized filename ordering (arc.groups)
AES/Blowfish/Twofish/Serpent encryption with keyfiles support and ability to chain multiple ciphers (-p, -hp, --keyfile, --encryption=ALGORITHMS)
FAR and Total Commander plugins allow to create/browse/extract archives using the file manager interface
Ability to create SFX (self-extracted) archives and installers
Ability to list/extract archives directly from Internet: arc x http://freearc.org/demo/arc.arc *.h
Archive protection and recovery, including recovery over Internet driven by CRCs of archive sectors (r/rr/-rr/--original=URL)
Ability to test archive before and after any operation (-tp/-t), including checking by recovery record and full archive test
Moving to archive (m), joining archives (j), archive recompression (ch), locking (k) and commenting (-z/cw)
Select files by size, time/age and name (-sl, -sm, -ta, -tb, -tn, -to, -n), select by/clear ARCHIVE file attribute (-ao/-ac)
Base directory on disk / inside archive (-dp/-ap), automatic generation of archive filenames (-ag)
Errors and warnings are reported to stderr and reflected in program exit code; --logfile option saves to the file all the information displayed
Configurable via arc.ini file and FREEARC environment variable; alternative settings may be selected by means of -cfg/-env options

Compared to RAR and 7-zip, FreeArc at this moment lacks the following: multi-volume archives, 64-bit version, storing of file attributes/extended timestamps/NTFS streams in the archive, bcj2, data segmentation. These are planned to be fixed in subsequent versions.

This is the best archiver i have found, i compressed a game which was 10GB big, winrar was 5GB, 7zip was 4.5GB and freearc was 3.5GB.

http://www.freearc.org/

http://www.freearc.org/Download.aspx

forgot to say, compression was around 1 hour,
decompression time was 10 minutes