High-speed dial-up works by compressing web pages, images, and text to accelerate the transfer of data over traditional dial-up connections. It uses techniques like on-the-fly compression, filtering of unnecessary content like pop-ups, and caching of frequently accessed content on the server and client-side to reduce load times. Testing showed that popular websites loaded 2 to 5 times faster with high-speed dial-up compared to standard dial-up.