When you install SharePoint, 5% of the server memory is automatically allocated to the distributed cache service’s cache size. The maximum amount of memory that can be allocated to the distributed cache size is 16GB per cache host in the server farm, and the maximum number of hosts per cluster is 16. That is a lot of fast memory to play with. For servers with more than 320GB of memory, should you have such a problem, you must plan to reconfigure the memory allocation of the distributed cache size to take full advantage of the server’s capacity. This is because 5% of 320GB is 16GB, and you would hit the maximum limit for out-of-the-box configuration.