Pre-install some packages in the global cache but dotnet restore runtime is increasing

[jinweili1]

I pre-installed some packages in the global nuget cache folder by using nuget install packages.config to reduce package download time when run restore command before build.
And it works, it hits local cache and just downloads missing packages.
But the dotnet restore command runtime is increasing.
After finding log, it always staggers in checking compatibility:

I want to know what causes this?

To Reproduce

Install thousands of packages and packages have different versions in nuget global cache folder.
Then run dotnet restore *.sln -v d can reproduce it.