passthrough graphics card to virtualbox

This feature is not yet supported in Virtualbox.

Your only alternative virtualization software that supports this that I am aware of are Qemu and Xen and possibly VMWare. Most success tales of passing through GPUs to virtual machines come from either Qemu or Xen so I would suggest you turn towards that until Virtualbox supports this.

There is a blog devoted to the subject(that is their 2015 tutorial on how to do this with qemu as a focus) which you may want to look into.

Keep in mind that VGA Passthrough is still very experimental technology and it requires Motherboard/CPU combinations that support very specific features, and usually it also requires a custom kernel configuration to actually be able to access these features from within Linux (to be able to use them in the virtual machine).

In light of this, please try not to overcommit. You are very likely to run into bugs or issues that can render either your physical or virtual system unstable or in some ways inoperable while using VGA Passthrough. Don't expect it to work completely, nor easily. You need luck for that to really happen.

It can't be done.

You can pass through USB devices, no problem. But when you start dealing with PCI and PCIe devices, they will not get passed through. In theory, if you disabled your graphics card until you booted your host OS, then enabled your graphics card "magically", your VM would still need full control over it (which your OS won't give you). It's not going to be possible given current technology

Okay, so it seems that it can be done, however what is important is the graphics card and chipset that are being used. In my case, processor and motherboard are fine, but graphics card is not :( but good news for the rest of you. Also it seems that the feature is better supported in xen or kvm than virtual box, see http://forums.linuxmint.com/viewtopic.php?f=42&t=112013