This site explains the key differences between vSphere 6.0 and vSphere 6.5. An overview comparison from all vSphere Versions is available here.
| vSphere 6.0 | vSphere 6.5 | |
| Released | March 2015 | November 2016 |
| Physical CPUs per host | 480 | 576 |
| Physical RAM per host | 12 TB | 12 TB |
| VMs per host | 1024 | 1024 |
| vCPU per VM | 128 | 128 |
| vMEM per VM | 4 TB | 6 TB |
| Cluster Size | 64 | 64 |
| High Availability | Reactive HA | Proactive HA |
| vSphere Integrated Containers | NO | YES |
| VM Hardware Version | 11 | 13 |
| VMFS Version | 5.61 | 6.81 |
| Management | vSphere Web Client vSphere Client (C#) | vSphere Web Client HTML5 Client |
| Authentication Management | Platform Services Controller | Platform Services Controller |
| vMotion | vMotion across vCenters vMotion across vSwitches | vMotion across vCenters vMotion across vSwitches Cross-Cloud vMotion |
| vMotion Network Support | L3 Network max. 100ms RTT | L3 Network max. 100ms RTT vMotion Traffic Encryption |
| Win to vCSA Migration | vCenter 5.5 to vCSA 6.0 | vCenter 5.5 to vCSA 6.5 vCenter 6.0 to vCSA 6.5 |
| REST API | NO | YES |
| VM Encryption | NO | YES |
| Virtual Volumes | Virtual Volumes 1.0 | Virtual Volumes 2.0 |
| Virtual SAN | VSAN 6.0 / 6.1 / 6.2 | VSAN 6.5 |
| vCenter Type | Windows Linux (vCSA) | Windows Linux (vCSA) |
| vCenter HA | NO | YES |
| vCenter Native Backup | NO | YES |
| vCSA Scale (vPostgres) | 1000 Hosts 10000 VMs | 2000 Hosts 25000 VMs |
| vCSA Operating System | SUSE Enterprise 11 | Photon OS |