Helping thread :)

[felice2011]

@aswadd ...lzmax64.exe ... is the 64 version should use all the processor cores.

Also uses this scheme, to move in the right direction for optimal settings.

a=[0|1] : ( Defaul 1 ) : Sets compressing mode

a=[0|1] : Sets compression mode: 0 = fast, 1 = normal. Default value is 1.

mf={MF_ID} : ( Defaul 1 ) : Sets Match Finder

mf={MF_ID} : Sets Match Finder for LZMA. Default method is bt4. Algorithms from hc* group don't provide a good compression ratio, but they often work pretty fast in combination with fast mode (a=0). Memory requirements depend on dictionary size (parameter "d" in table below).
             
             MF_ID 	Memory 	Description
             bt2 	d*9.5 + 4 MB 	Binary Tree with 2 bytes hashing.
             bt3 	d*11.5 + 4 MB 	Binary Tree with 3 bytes hashing.
             bt4 	d*11.5 + 4 MB 	Binary Tree with 4 bytes hashing.
             hc4 	d*7.5 + 4 MB 	Hash Chain with 4 bytes hashing.

    Note: Your operation system also needs some amount of physical memory for internal purposes. So keep at least 32MB of physical memory unused.

d={Size}[b|k|m] : ( Defaul 24 )	: Sets Dictionary size

d={Size}[b|k|m] : Sets Dictionary size for LZMA. You must specify the size in bytes, kilobytes, or megabytes. The maximum value for dictionary size is 1 GB = 2^30 bytes. Default values for LZMA are 24 (16 MB) in normal mode, 25 (32 MB) in maximum mode (-mx=7) and 26 (64 MB) in ultra mode (-mx=9). If you do not specify any symbol from the set [b|k|m], the dictionary size will be calculated as DictionarySize = 2^Size bytes. For decompressing a file compressed by LZMA method with dictionary size N, you need about N bytes of memory (RAM) available.

fb={NumFastBytes} : ( Defaul 32 ) Sets number of Fast Bytes for Deflate encoder.

fb={NumFastBytes} : Sets the number of fast bytes for the Deflate/Deflate64 encoder. It can be in the range from 3 to 258 (257 for Deflate64). Usually, a big number gives a little bit better compression ratio and a slower compression process. A large fast bytes parameter can significantly increase the compression ratio for files which contain long identical sequences of bytes.

mc={N} : ( Defaul 32 ) : Sets Number of Cycles for Match Finder

mc={N} : Sets number of cycles (passes) for match finder. It can be in range from 0 to 1000000000. Default value is (16 + number_of_fast_bytes / 2) for BT* match finders and (8 + number_of_fast_bytes / 4) for HC4 match finder. If you specify mc=0, LZMA will use default value. Usually, a big number gives a little bit better compression ratio and slower compression process. For example, mf=HC4 and mc=10000 can provide almost the same compression ratio as mf=BT4.

lc={N} : ( Defaul 32 ): Sets number of Literal Context bits - [0, 8]

lc={N} : Sets the number of literal context bits (high bits of previous literal). It can be in range from 0 to 8. Default value is 3. Sometimes lc=4 gives gain for big files.