This enables up to 6 displays to be used independently. In addition, support for 3D stereoscopic systems enables the use of 3D glasses at the high screen refresh rates required. Hardware support is included for DirectX 11 and OpenGL 4.0, and support is also given for the OpenCL standard. For increased processing power, a number of video cards can be linked in tandem through the use of ATI CrossFire Pro technology. This card uses the PCI-E 2.1 standard.