The gzip command itself is single threaded, but you can replace it on system with pigz, or provide extra arguments to the ‘tar’ command itself, which will give you a significant speed-up..
From the tar manpage:
-I, --use-compress-program PROG filter through PROG (must accept -d)
So, typical tar options to compress and extract files with tar plus pigz might be…
tar -I pigz -cf test.tar.gz * tar -I pigz -xf test.tar.gz