Why the difference?

[HandsomeGuy]

Why is there a difference in 7z file sizes when I compress using PA and 7-zip file manager? Mostly, PA gets smaller archive sizes. Sometimes its because of missing file/folders (discussed elsewhere), but other times, all files being intact, PA 7z files are slightly smaller.

Why is this, considering you can modify a lot more memory settings in 7-zip file manager compared to PA. What sort of options does PA use in comparison with 7-zip file manager in terms of these additional settins that cannot be changed in PA?

[spwolf]

PA uses predefined 7zip settings. When you manually change these settings, you need to test it out several times to find the best setting for that situation - simply putting everything to the highest level in 7zip might not create the smallest file.

[HandsomeGuy]

Fair enough. But what other settings can you change in PA regarding 7z? Theres the compression mode, thats about it. And solid archive settings. PA doesn’t have all the memory settings to change that 7-zip File Manager does.

[ivan]

No, right now no, but this may be considered for future versions. Our methods use standard 7-ZIP predefined options (memory, dictionary, …) for those methods.

[HandsomeGuy]

@ivan:

No, right now no, but this may be considered for future versions. Our methods use standard 7-ZIP predefined options (memory, dictionary, …) for those methods.

What exactly are those numbers and figures, so I can try those same settings on 7-zip file manager and check out the size of its files.

[ivan]

Same as when you use -x switch with 7-ZIP command line (-x=0 for store, -x=9 for ULTRA)

Copied for 7-ZIP Help file:

STORE - No compression.

Fast compressing: fast LZMA mode, 32KB dictionary, HC3 Match finder, BCJ filter.

Normal compressing: normal LZMA mode, 2 MB dictionary, BT4 Match finder, NumFastBytes is 32, BCJ filter.

Maximum compressing: maximum LZMA mode, 8 MB dictionary size, BT4 Match finder, NumFastBytes is 64, BCJ filter.

Ultra compressing: maximum LZMA mode, 32 MB dictionary size, BT4b Match finder, , NumFastBytes is 64, BCJ2 filter.

When using Solid, the size of solid block are:

Store 0 B
Fast 16 MB
Normal 256 MB
Maximum 1 GB
Ultra 4 GB