FAQ: What is optimized 7-Zip compression?
7-Zip Optimized Compression in PowerArchiver
What is it?**
From PowerArchiver 2009, we have added feature called Optimized 7-Zip compression. This feature is currently unique to PowerArchiver 2009.
With Optimized Compression we have tried to solve one of the most important issues that 7-Zip has when compared to ZIP and RAR formats, which is speed and automatic detection of content being compressed.
What does it do?
With Optimized compression feature on, PowerArchiver tries to smartly detect files that are being compressed and assign special compression methods to improve either speed or compression. In the case of text files, it automatically uses PPMd compression for them (instead of LZMA) which has a lot better compression ratio and is also faster. For files that can not be compressed further, it uses different LZMA settings to speed up compression without losing compression strenght. It also works great with solid setting on, which is reccomended as not only it increases compression strenght but also speed as well.
Results are double the compression strenght on text files, and double the speed on files that can not be compressed (mp3, avi, mpeg, etc). Obviously these are the best case scenarios, and in real life usage it depends on data that you are trying to compress.