Performance and Efficiency Differences

Historically, HTTPS carried a reputation for slower performance compared to HTTP due to the computational overhead of encryption and the additional round trips required for the SSL/TLS handshake. Early implementations could add noticeable latency, particularly on mobile devices with limited processing power. This performance penalty led many sites to use HTTPS selectively, protecting only sensitive pages while serving other content over HTTP.

Modern HTTPS implementations have largely eliminated these performance concerns through various optimizations. Hardware acceleration for cryptographic operations, available in most modern processors, makes encryption negligible in terms of CPU usage. Session resumption mechanisms allow clients to reconnect to servers without repeating the full handshake. OCSP stapling eliminates the need for separate certificate revocation checks. TLS 1.3 reduces the handshake to a single round trip, and can even enable zero round-trip resumption for returning visitors.

Paradoxically, HTTPS now often provides better performance than HTTP due to protocol improvements. HTTP/2, which most browsers only support over HTTPS, enables multiplexing multiple requests over a single connection, server push capabilities, and header compression. These features can significantly improve page load times compared to HTTP/1.1. HTTP/3, built on QUIC, takes these improvements further while maintaining the HTTPS requirement, cementing the connection between security and performance.