I've seen many SQL configurations which would seem optimal at first glance but the disk is working constantly and performance is not very good, those servers could have been a lot better if one thing is set. The SQL Maximum Server Memory. I think I've read somewhere that it could be calculated, some think it should be set at the server's physical memory, but in my opinion and in my experience, no effort is needed, just a fresh restart, wait for everything to load, and take a look in Available memory in the task...