The NonSharedSerializer creates new instances of the JMS Serializer for every serialization / deserialization call.

The problem is that several hundred or thousands of calls can be made per request (e.g. when using loadContent() with a content object that has a page field.

The JMS Serializer will reload the config file for every single call. This will create lots of Disk I/O and stall the CPU, especially when not using an SSD hard drive.