No. Object Caches such as APC, Memcached or Redis are not mandatory to enable in WordPress by using a WordPress plugin or drop-in. We are talking in the context of dedicated servers. A persistent Object Cache is worthless to use on a single virtualized instance such as one VPS or one cloud server. The reason is that 100% of the RAM is not real RAM, there is swap space i.e. SSD space. When you … [Read more...]