This page is a stub. Help by expanding it. An OpenCL miner is a bitcoin miner that uses the OpenCL framework to perform the hashing computations. When used with a modern GPU, this can produce hash rates orders of magnitude higher than what can be achieved with a CPU. Hashing on a GPU requires an OpenCL or CUDA compatible graphics card (NVIDIA, ATI/AMD).
The python Poclbm open source OpenCL bitcoin miner was created by m0mchil based on the open source CUDA client originally released by puddinpop. Subsequently the java DiabloMiner based on m0mchil's was created by Diablo-D3. Puddinpop has also released a C++ OpenCL client capable of being compiled into the GUI client or daemon, or as a stand alone RPC miner.
See the Mining Hardware Comparison page for detailed statistics on the hash rates that can be achieved with various hardware.