I did some benchmarking on a 1.6 GiB file in order to check the performance of different deflate tools:

The memory usages were as follows when compressing the file:

• gzip 1.5M
• pigz (one thread) 2.4M
• igzip 3.5M
• libdeflate-gzip 1.6G

When decompressing the resulting file

• gzip 744K
• pigz (one-thread) 1.2M
• zstd (from .gz) 2.2M
• igzip 3.6M
• libdeflate-gzip 2.2G

This is quite a big difference between the different applications and libdeflate-gzip. It uses 3 orders of magnitude more memory than the others.
This was using version 1.6.