VirtualBox v4.3 Beta 3 is released. VirtualBox is a general-purpose full virtualizer for x86/x64 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.

VirtualBox v4.3 Beta 3 Changelog:
VMM: implemented thread-context hooks for Linux and Solaris hosts
VMM: several fixes
GUI: added NAT networks to the global settings page
GUI: made NAT network a separate network attachment type
3D Support: fixed Google Chrome and IE rendering under Window 8.1
3D Support: fixed DXDiag crashes mentioned here
NAT service: several fixes
Main: eliminate the use of SysV semaphores on all host OSes other than Windows, namely Linux, Solaris and Mac OS X, with the consequence that no system reconfiguration is needed to run more than approximately 100 VMs
Windows hosts: fixed crashes on Windows 8.1
Linux hosts: fix hanging GUI on EL4 and EL5 distributions with old libX11 versions
Linux Additions: Linux 3.11 shared folders fix
Linux Additions: Linux 3.12 fixes

Download: VirtualBox v4.3 Beta 3
Source: Here