In OpenCL you need to copy items from the system memory to the GPU's memory and then load the kernel on the GPU to start execution. Then you must copy the data back from the GPU's memory at the end after execution. AMD is saying that you can instead pass a pointer to the data in the main memory instead of actually making copies of the data.
This should reduce some of the memory shifting on the system and speed up OpenCL execution. It will also eliminate some of the memory constraints on OpenCL regarding what you can do on the GPU. On a larger scale it will open up some opportunities for optimizing work.
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