Controls whether the multi-threaded match finder is enabled on the LZMA and LZMA2 compressors. Enabling the multi-threaded match finder can speed up the compression process by 50% or more on systems with multiple processor cores, and 20% or more on systems with Intel processors featuring Hyper-Threading Technology.

A value of auto (the default) enables the multi-threaded match finder for all compression levels except fast, which doesn't support it.

A value of 1 always disables the multi-threaded match finder.

Values of 2 or higher are currently equivalent to auto.

Note that for the LZMA2 compressor, this directive only controls whether the multi-threaded match finder is used. To enable support for compressing multiple parts of large files in parallel, set LZMANumBlockThreads.

See also:
LZMANumBlockThreads