I just stumbled upon REP a compression preprocessor.
and did this little test which impressed my a lot.
Dreamfall.mdf - 4.00GB
Dreamfall.mdf.rep - 3.66GB
Dreamfall.7z (ultra 3.68
After decompression i did a CRC32 verify and the files was the same.
why i was impressed is beacuse it did it very faster then 7-zip