VirtualBox 5.1 (released 2016-07-12)

Es un programa que permite ejecutar otros sistemas operativos en tu ordenador como por ejemplo Linux, Windows xp,Windows 98 (Sin aceleración gráfica), windows 95 (Sin aceleración gráfica), es parecido en siu uso y funcionamiento a vmware aunque no son compatibles las maquinas creadas entre ellos, se trata de una alternativa que aunque no sea tan buena va mejorando en cada versión y que es una buena opción para emular algunos juegos de pc antiguos que pueden no funcionaren vmware..

Cambios:
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)


Paágina oficial:
https://www.virtualbox.org/

Descarga la versión windows 32 y 64 aqui:
http://download.virtualbox.org/virtualbox/5.1.0/VirtualBox-5.1.0-108711-Win.exe

Linux:
https://www.virtualbox.org/wiki/Linux_Downloads