Simply put: Download and use it and see for yourself how fast it is!!
Download link: http://www.mozilla.com/en-US/products/download.html?product=firefox-4.0b7&os=win&lang=en-US
Update Summary from PC MAG:
http://www.pcmag.com/article2/0,2817,2372496,00.asp
Download link: http://www.mozilla.com/en-US/products/download.html?product=firefox-4.0b7&os=win&lang=en-US
Update Summary from PC MAG:
JavaScript improvements, more support for accelerated graphics, and even 3D support.
http://www.pcmag.com/article2/0,2817,2372496,00.asp