Intro

So you downloaded a file from the internet with a .7z file extension.  Maybe you don't know what this thing is; why does someone put 'unzip it' when it is not a typical .ZIP file?

Let Daedalus show you the way!  ^_^

The 7-zip program is a file archiver with a high-compression ratio.  When I asked Skopin to recompress their hefty texture files with 7-zip, the resulting .7z files were merely 10% of the size of the original!  From ~550 MB to ~55 MB!



Instructions to extract .7z files
Presuming Windows OS (Linux-based OS users are generally able to figure things out):

1 - Download 7-zip from the official website.  You can also get an officially-packed certificate-signed portable version from PortableApps.com

2 - Be sure you unblock your download before doing anything else.  If you have an OS prior to Win10 and haven't updated lately, you may not see the button.  If this is the case then skip to the next step.

3 - Right click the installer file and RUN AS ADMIN.  Click the 'Install' button and then 'Close' when the installation is complete.

4 - If you want to configure integrations (if not using portable mode) so that files are opened automatically in 7-zip, then keep going.  Otherwise, this is all you need.

5 (EXTRA) -- Open the main EXE file as ADMIN: %PROGRAMFILES%\7-Zip\7zFM.exe.
5a -- Go to Tools -> Options -> System tab -> Click the + sign under your username and/or all users for file associations
5b -- Under the tabs for 7zip, Settings, and Language be sure to select your preferences
5c (WIN10 Only) -- Under Settings tab, be sure to UNCHECK 'Use Large Memory Pages' if you are running any version of Windows 10 due to a bug with that OS.  If you want to test if the bug is fixed in newer Win10 updates, then please reference this forum post and follow the instructions there.



Optimal 7-zip Compression Settings

After extensive testing with a variety of files, I've found the following settings to be the best compression settings on my system.  As usual, things may be more/less optimal depending on your system hardware specifications.  Be aware that these compression settings take a significant amount of time for compression & decompression but achieve some of the smallest file sizes around! 

I have a Quad-Core (4 core) CPU so if you have more/less then adjust the 'CPU Threads' as needed.  Also feel free to experiment a bit if your time/inclination desires to do so.  ^_^