I was suspicious, I just could not put my finger on it :) for i in 0..<iterations { let result = flatuseStruct(outputData, start:i) assert(result

I was suspicious, I just could not put my finger on it :) for i in 0..<iterations { let result = flatuseStruct(outputData, start:i) assert(result == 8644311666 + Int(i)) total2 = total2 + UInt64(result) } this results in around 42ms compared to C 25ms. I guess I should update my blog post :) Thanks for your help.