Constant / global memory

Constant Memory is faster because the constant memory cache is implemented onchip. Global memory resides offchip so it's slower. Note that the data should ideally fit inside the constant memory. If it doesn't and there's a cache miss, the fetch operation for the constant cache is expensive. To change the size of the constant cache you can use the --const-cache-bytes <N> where N is the number of bytes you want the cache to be