Large hires renders can take many, many hours, even days to render.

Maybe your bucket size is too large also? In your render settings, try a smaller bucket size (8, 16, 32, 64, 128).  However, note that a smaller bucket size can also add time to the render time, but it can also help prevent the dreadful "out of memory" error part way through the render process.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi