As I mentioned in another comment, the minigzip used is very suboptimal due to reading and decompressing only 1 byte per inflate() call. Please retest with --zlib-compat or the fix that was merged today.
I'm not in the habit of including compression level 6 in the results, since the application I care about defaults to 5 :) And I wanted a good spread of different compression levels in the results.
Results with zlib-ng and a newer version of the Cloudflare changes:
https://www.snellman.net/blog/archive/2015-06-05-updated-zli...
Original:
Here are some benchmarks of the Intel and Cloudflare forks that this project is based on:
https://www.snellman.net/blog/archive/2014-08-04-comparison-...
The speedups are not insignificant. (I'll see about updating the post to include results for zlib-ng).