Cypress 3.3.0 achieved a substantial 300% increase in network speed by addressing performance issues with its HTTP proxy, which initially caused significant slowness compared to standard browsers. The Cypress proxy plays a crucial role in testing by intercepting and modifying HTTP requests, but it initially introduced a delay in the time-to-first-byte (TTFB) due to the Nagle algorithm, which buffered data unnecessarily. By disabling this algorithm, Cypress improved TTFB and overall performance to near parity with a regular browser. Additionally, version 3.3.0 introduced enhancements like corporate proxy support, improved network error handling, and laid groundwork for future capabilities such as full network stubbing and HTTP/2 support. These changes not only optimized test execution speed but also enhanced the reliability and flexibility of network interactions in testing environments.