In a standard ZIP, each file is compressed individually. In a "solid" 7z archive, all files are treated as one massive data block.

Knowing the software you're using can help troubleshoot the issue.

Unlike some proprietary formats, 7-Zip is open-source and widely considered safe for distributing large software packages.

If you have many similar files (like versions of the same document or many ROMs from the same console), 7-Zip can find patterns across all of them, resulting in a significantly better compression ratio.

The "catch" with solid archives is that if you want to extract just one small file from the middle of a huge archive, your computer might have to process the entire block before it can "find" that specific file. Additionally, if a solid archive is corrupted, you might lose every file in that block rather than just one. Why You See It Everywhere (Especially Games)

The .7z extension is a staple in the gaming and emulation communities for a few reasons: