Google PageSpeed is the more common of the two in our index: it runs on 96 websites against 14 for mod_ssl. Counts come from real scans, not vendor claims.
Google PageSpeed is a family of tools designed to help websites performance optimisations.
mod_ssl is an optional module for the Apache HTTP Server. It provides strong cryptography for the Apache web server via the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) cryptographic protocols by the help of the open-source SSL/TLS toolkit OpenSSL.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.