Apple claimed that Mac OS X 10.4 Tiger was the most successful Apple OS release in the company's history. Six weeks after its official release, Apple had delivered 2 million copies of Mac OS X 10.4 Tiger, representing 16% of all Mac OS X users. The server edition, Mac OS X Server 10.4, was also available for some Macintosh product lines. Mac OS X 10.4 Tiger was included with all new Macs, and was also available as an upgrade for existing Mac OS X users, or users of supported pre-Mac OS X systems. Mac OS X 10.4 Tiger offered a number of features, such as fast file searching and improved graphics processing, that Microsoft had spent several years struggling to add to Windows with acceptable performance. Some of the new features included a fast searching system called Spotlight, a new version of the Safari web browser, Dashboard, a new 'Unified' theme, and improved support for 64-bit addressing on Power Mac G5s. Tiger was released to the public on Apfor US$129.95 as the successor to Mac OS X 10.3 Panther. Mac OS X Tiger (version 10.4) is the fifth major release of macOS, Apple's desktop and server operating system for Mac computers.