the scheduling work performed includes prioritized queues which allow critical tasks to run at a higher priority than other tasks without requiring the lower priority tasks to be preempted to run the high priority task, therefore allowing the tasks to run concurrently with the high priority tasks scheduled to hog the GPU as much as possible while letting other tasks use the resources that the high priority tasks are not using. These are essentially Asynchronous Compute Engines that lack dispatch controllers. They were first introduced in the fourth generation GCN microarchitecture, but were present in the third generation GCN microarchitecture for internal testing purposes. A driver update has enabled the hardware schedulers in third generation GCN parts for production use. Primitive Discard Accelerator This unit discards degenerate triangles before they enter the vertex shader and triangles that do not cover any fragments before they enter the fragment shader. This unit was introduced with the fourth generation GCN microarchitecture. Generations Graphics Core Next 1 The GCN 1 microarchitecture was used in several Radeon HD 7000 series graphics cards. support for 64-bit addressing (x86-64 address space) with unified address space for CPU and GPU support for PCI-E 3.0 GPU sends interrupt requests to CPU on various events (such as page faults) support for Partially Resident Textures, which enable virtual memory support through DirectX and OpenGL extensions AMD PowerTune support, which dynamically adjusts performance to stay within a specific TDP support for Mantle (API) There are Asynchronous Compute Engines controlling computation and dispatching. ZeroCore Power ZeroCore Power is a long idle power saving technology, shutting off functional units of the GPU when not in use. AMD ZeroCore Power technology supplements AMD PowerTune. Chips Discrete GPUs (Southern Islands family): Hainan Oland Cape Verde Pitcairn Tahiti Graphics Core Next 2 The 2nd generation of GCN was introduced with the Radeon HD 7790 and is also found in the Radeon HD 8770, R7 260/260X, R9 290/290X, R9 295X2, R7 360, and R9 390/390X, as well as Steamroller-based desktop "Kaveri" APUs and mobile "Kaveri" APUs and in the Puma-based "Beema" and "Mullins" APUs. It has multiple advantages over the original GCN, including FreeSync support, AMD TrueAudio and a revised version of AMD PowerTune technology. GCN 2nd generation introduced an entity called "Shader Engine" (SE). A Shader Engine comprises one geometry processor, up to 44 CUs (Hawaii chip), rasterizers, ROPs, and L1 cache. Not part of a Shader