Firefox 27 System Requirements
Operating Systems

Windows XP SP2
Windows Server 2003
Windows Vista
Windows 7
Windows 8

Please note that while the 32-bit and 64-bit versions of Windows Vista and Windows 7 can be used to run Firefox 27, only 32-bit builds of Firefox 27 are supported at this time.
Recommended Hardware

Pentium 4 or newer processor that supports SSE2
512MB of RAM
200MB of hard drive space

Operating Systems

Mac OS X 10.6
Mac OS X 10.7
Mac OS X 10.8
Mac OS X 10.9

Recommended Hardware

Macintosh computer with an Intel x86 processor
512 MB of RAM
200 MB hard drive space

Software Requirements
Please note that Linux distributors may provide packages for your distribution which have different requirements.

Firefox will not run at all without the following libraries or packages:
GTK+ 2.18 or higher
GLib 2.22 or higher
Pango 1.14 or higher
X.Org 1.0 or higher (1.7 or higher is recommended)
libstdc++ 4.3 or higher
For optimal functionality, we recommend the following libraries or packages:
NetworkManager 0.7 or higher
DBus 1.0 or higher
HAL 0.5.8 or higher
GNOME 2.16 or higher