Calling require/require_relative inside of the storeconfigs setting hook is really slow on Windows: https://github.com/puppetlabs/puppet/blob/75737603872883d8d72224e2a6857804938f9634/lib/puppet/defaults.rb#L2122-L2123
It appears to add several minutes to the overall rspec time on Windows.
The issue is on_initialize_and_write hooks are called at the start of every test, so we're calling require/require_relative about ~40k times.
Also the factpath setting has a similar hook and we keep appending the same 2 directories to the facter search path.
Merged to 6.x in https://github.com/puppetlabs/puppet/commit/b5e3d4e5a206010119f4c67b36c94983cae32d65