VirtualBox 5.1

virtualbox

VirtualBox is a powerful x86 and AMD64/Intel64 virtualization product for enterprise as well as home use. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.

Some of the features of VirtualBox are:

Modularity. VirtualBox has an extremely modular design with well-defined internal programming interfaces and a client/server design. This makes it easy to control it from several interfaces at once: for example, you can start a virtual machine in a typical virtual machine GUI and then control that machine from the command line, or possibly remotely. VirtualBox also comes with a full Software Development Kit: even though it is Open Source Software, you don't have to hack the source to write a new interface for VirtualBox.
Virtual machine descriptions in XML. The configuration settings of virtual machines are stored entirely in XML and are independent of the local machines. Virtual machine definitions can therefore easily be ported to other computers.

Version 5.1 is a major update. The following major new features were added:

VMM: new APIC and I/O APIC implementations that result in significantly improved performance in certain situations (for example with networking, bug #15295)
VMM: added support for Hyper-V paravirtualized debugging of Windows guests
VMM: emulate even more MMIO and shadow pagetable exits without going back to user mode
GUI: overall migration to Qt5 (bug #11775)
GUI: passive API event listener improving the VM GUI performance and response time
Audio: added HDA (High Definition Audio) support for newer Linux guests
Audio: added on-demand timers which should improve the overall performance and reduce the CPU consumption
Audio: more fine-grained volume control for the AC'97 emulation, which now also takes the master volume control into account
better support for Python 3

In addition, the following items were fixed and/or added:

VMM: activate the x2APIC by default for Linux guests
VMM: many more fixes
GUI: the Detach UI action is now a part of the VM Machine menu
GUI: reworked session information window
GUI: the new VM wizard now allows to choose the VM location for the VM which is being created
GUI: fixed location of touch events in unscaled HiDPI mode (bugs #14366, #14367)
GUI: various bugfixes and internal cleanup
Storage: use fallocate() or similar if present to speed up creating fixed-sized disk images (bug #5967)
Storage: implemented NVMHCI-compatible storage controller
Audio: various bugfixes and infrastructure improvements
E1000: implemented interrupt throttling for performance improvements
EFI: many improvements, for example allow to boot from USB
OVF: improved handling of signed manifests
API: Windows XP guests and Windows 2003 server guests now default to the E1000 T Server network card
VBoxSVC: fixed several memory leaks when handling .dmg images
Installers: ship VBoxBugReport
Windows hosts: reworked COM proxy (e.g. bug #8298)
Linux installers: no longer rely on DKMS for module rebuilding
Linux Additions: fix a problem when updating the initramfs after the guest modules are compiled (bug #15579)
Linux Additions: try to fix a problem where the OpenGL libraries where loaded by the X server when we only support X clients (bug #15574)