As of 2023: The default command seems to take advantage of all my cores (32 core AMD CPU) and uses max compression.
When my folder has only one file inside, the cpu usage is low. If there are many large files, the cpu usage grows beyond 50%. Which I think explains why some people think it is not working?
I use the following PowerShell script to compress all sub-dirs into their own 7z archives.
EG: It takes a dir with sub-folders: A, B, C and outputs: A.7z, B.7z, C.7z
You can see the actual 7zip command on the last line, I have no flags set other than:
-bsp1
for verbose logging and this ends up using all my cores when needed.
$rootDir = Get-Location # Can select the parent dir here
$7zipPath = "7z.exe" # Replace with the path to 7zip if not in PATH
Get-ChildItem -Path $rootDir -Directory | ForEach-Object {
$folderName = $_.Name
$outputFile = Join-Path $rootDir "$folderName.7z"
& $7zipPath a -bsp1 $outputFile $_.FullName
}