winrar what files is it really for

i wanted to use a compressin app for avi and xvid files but now know this is slightly pointless, cause it decreases size by only about 1%. I tried 7z, zipgenius, and winrar. What are these zip files really for. I hear that u can get 50% or maybe 20% on certain files but what kind of files are they really talking about? jpegs or text or what?

 

Compression tools are best for uncompressed data (Like WAV, BMP, TXT files). JPEGS, MP3, WMV are already compressed and receive no benefit besides being grouped together in a single file.

 

what he said

however, if you're trying to move a large video file, winrar makes it very easy to split the archive into pieces that can be easily assembled on the recieving end simply by extracting the first file in the series.