KGB Archives is an tool which can be made either in KGB or ZIP format and you can select the level of compression technique to compress!
I compressed 1.2Mb file to 366,5Kb at Maximum level compression!!
This tool is powerful but it takes long time for the extreme or maximum compression level.
When the application is open but has no active tasks, system memory is considerably used but when a file is being compressed, the numbers are skyrocketing!!!