As more VDI workloads are demanding high-power Graphical Processor Units (GPU) for things like 3D graphics and CAD, vendors are allowing the virtualization and passthrough of physical GPU cards in the hypervisor hosts. Microsoft has written a detailed article on how this is donw on Windows Server 2012 with RemoteFX.
The vGPU feature of RemoteFX makes it possible for multiple virtual machines to share a physical graphics adapter. The virtual machines are able to offload rendering of graphic information from the processor to the dedicated graphics adapter. This will decrease the CPU load and improve the scalability for graphic intense workloads that run in the VDI virtual machines.