VMware vSphere 6.5 offers increased scalability. You can see a comparision against all previous verisons at my ESX and vCenter Configuration Maximums page. Changes in VMware vSphere 6.5 are:
Virtual Machine and Host Maximums
| vSphere 6.5 | vSphere 6.0 | |
| RAM per virtual machine | 6 TB | 4 TB |
| Video memory per virtual machine | 2 GB | 512 MB |
| Logical CPUs per host | 576 | 480 |
| Number of total paths on a server | 2048 | 1024 |
| FC LUN ID | 16383 | 1032 |
| Volumes per host | 512 | 256 |
vCenter Server Maximums
| vSphere 6.5 | vSphere 6.0 | |
| Hosts per vCenter Server | 2000 | 1000 |
| Powered on virtual machines | 25000 | 10000 |
| Registered virtual machines | 35000 | 15000 |
| Number of host per datacenter | 2000 | 500 |
| Virtual machines per cluster | 8000 | 4000 |
| Hosts per distributed switch | 2000 | 1000 |
Max VMs per cluster in 6.0 is 8000, same as 6.5