A67zip -

This mode is most effective when your archive contains many files of the same type or with similar content, as it "consolidates" the redundancy. Important Trade-offs

If a solid block becomes corrupted, you may lose access to all files within that specific block, whereas in a non-solid archive, a single error usually only affects one file. How to Use It A67zip

To extract a single file from the middle of a solid block, 7-Zip must decode all the data preceding it in that block, which can make extracting individual files slower. This mode is most effective when your archive

In 7-Zip, the compression feature treats multiple files as a single continuous data stream, which often results in significantly higher compression ratios, especially when archiving many similar files. Key Benefits In 7-Zip, the compression feature treats multiple files

Because 7-Zip can find patterns across different files rather than just within a single one, solid archives are usually much smaller than non-solid ones.