A graphics processing unit or GPU refers to hardware to assist a computer in graphics-intensive tasks. Macs currently use a range of graphics cards or have built-in GPUs. Newer iOS devices can contain more than one, for normal high-efficiency use, or for high performance use with accelerated graphics (for gaming, which may use more power).
Over the years Apple used ATI Radeon, nVidia GeForce and Intel GPUs, but began engineering their own for mobile devices.
- Graphics processing unit at Wikipedia