What is the best value for rawintensity? I tested 1152 and got the following:
RX 580 4GB - 770 H/s
RX 580 8GB - 860 H/s
For 4Gb 1152 is too much. For 1152 it's need more than 4Gb videomemory. Try for 4Gb 1024.
For both 4Gb and 8Gb speed on 1024 and 1152 is equal. With 2 threads and 8 localwork size.