If you enable this option Swift Performance will generate the GZIP version of all cached pages, also will generate the htaccess/nginx rules to enable GZIP compression for static files.

Swift Performance Autoconfig will disable this feature if find any rules in htaccess which already enables GZIP to avoid double GZIP errors.

However if you have double GZIP issues, you may need to disable this option.

Double GZIP issue

If you see something similar when pages are cached, it means you have double GZIP issue. Disable GZIP in Swift Settings » Caching to solve it