When archiving big dump files from the Oracle databases I maintain, 7-zip is the best compressor. But not with the default settings. The compression level in 7-zip format can also be adjusted. While this can be time consuming, I need to pull those archives through a slow(er) internet connection. The extra time I lose on archiving and unpacking pales in comparison with the time I need to spend on transferring these files.
1. 7-zip comes with a Gui application, but also with a version for scripts. When using both applications with the most extreme 7-zip (LZMA) compression setting, it would make sense to expect similar sized archives. Not true, the script version compresses significantly better. After compressing 1.6GByte of executables, dll's, images, HTML and other text-based scripts I end up with an archive that is around 280MByte in size when created with 7-zip GUI version. With the 7-zip script version the resulting archive varies between 180 to 190MByte.
2. Especially with big(ger) data files, you will notice an improvement in compression speed and resulting archive size when you set 7-zip to ultra and change the dictionary size to 32MByte and the word size to 256. Those settings are not the default, but make quite a big difference in my case. Playing with these settings can have both positive and negative effects and compression time and archive size. But it does pay off to play a bit with these settings.
All in all, 7-zip compresses way better than zip does for me. And as I don't have a need for Windows to index my archives, I gain a lot more storage space this way. However, in case you need to have archive content indexed by Windows, as xtabber states, there could be something interesting here at this link
. There you can download a piece of software that can replace the Microsoft Zip functionality with the raw power and options of 7-zip, directly from within the Windows Explorer. No, not an extra context menu item, really replace MS zip with 7-zip. That way you have the best of both worlds.