Firefox 3.0 recorded usage share of web browsers. Estimates of Firefox 3.0's global market share were generally in the range of 4–5%, and then dropped as users migrated to Firefox 3.5 and later Firefox 3.6. Partially as a result of this, between mid-December 2009 and the end of January 2010, Firefox 3.5 was the most popular browser (when counting individual browser versions), passing Internet Explorer 7. Mozilla ended support for Firefox 3 on March 30, 2010 with the release of 3.0.19. Firefox 3.0 was developed under the codename "Gran Paradiso". This, like other Firefox codenames, is the name of an actual place;
Chakra (JScript engine) Chrome (with V8), and Opera (with Carakan). On March 8, 2011, Microsoft published results showing the 32-bit Internet Explorer 9 to be faster than Safari, Firefox (with TraceMonkey), Chrome, and Opera. March 2011 performance tests for ZDNet concluded that Internet Explorer 9 (32-bit), Chrome 10, and Firefox 4 release candidate were "pretty evenly matched." In 2012, subsequent versions of Chakra, such as the version included in Internet Explorer 10, introduced additional performance changes, including JIT compilation on x64 and ARM architectures, and optimizations related to floating point math and garbage collection. At the Last Call JSCONF in 2015, Microsoft announced