Advanced compression parameters


This dialog contains a number of advanced compression options for RAR archive format. Their improper use may lead to suboptimal performance and compression. These options are described below.

Long range search

Enables the search algorithm designed to efficiently locate longer and more distant repeated data blocks. It can helps to improve the compression ratio and sometimes speed for redundant data like big text files. This algorithm increases memory requirements when archiving, but doesn't affect extraction memory requirements or speed.

If "Auto" is selected, WinRAR applies the long range search depending on the compression method, dictionary size and other parameters. "Always on" turns it on permanently. "Disable" turns it off. This algorithm is required and enabled automatically for dictionaries exceeding 4 GB, ignoring "Disable" option.

Long range search mode is applicable to "Fast" .. "Best" compression methods and ignored for "Fastest" one.

Delta compression

Splits data to several single byte channels and calculates the difference between them. Can improve the compression ratio of table data.

"Auto" mode applies it depending on the compression method. "Always on" turns it on permanently. "Disable" turns it off.

x86 executable compression

Can improve the compression ratio of 32 and 64 bit x86 executables.

"Auto" mode applies it depending on the compression method. "Always on" turns it on permanently. "Disable" turns it off.

Exhaustive search

Enables much slower and more exhaustive repeated data search and compression algorithm. It might provide the additional compression gain on some types of redundant data, but at much lower speed. Long range search is needed to implement this mode efficiently, so the exhaustive search option activates it automatically.

Default button

Reset all options of this dialog to default values.