ZF3 provides the following features to ensure its performance is acceptable:
Lazy class autoloading. Classes are loaded once needed.
You don't have to write
require_once for each class
you want to load. Instead, the framework automatically discovers your classes
using the autoloader feature.
Efficient service and plugin loading. In ZF3, classes are instantiated only when they really need to. This is achieved through service manager (the central container for services of your application).
Support of caching. PHP has several caching extensions (like Memcached) that can be used to speed-up ZF3-based websites. Caching saves frequently used data to memory to speed-up data retrieval.