There are 3 exams on each of the following NSX 6.4 topics;
NSX Components
Logical Switches
Distributed Logical Routers
Distributed Firewalls
Edge Gateways
High Availability
This is not a brain dump, this is summary of the VMware NSX documentation presented as an exam to verify your knowledge on the topic. If you're preparing for the exam, a thorough understanding of these components will ensure you're able to answer both simple and scenario based questions.