Personally, if the server load is around 4.00 24/7 and we're talking about a server with a single processor, I would suspect something is wrong: overselling or overloading. In that case, just to make sure I would never face serious problems, I would ask my host to do something about the server load or move my website to a server with a lower server load. If the response I get does not please me, I will consider looking for a new host.