VMware View has always automatically calculated video RAM based on resolution and color depth. Up to VMware View 4.6, only 24-bit color depth was supported and VMware published the vRAM overhead that each resolution type would require. vRAM overhead is part of the VM memory overhead in virtual machines running on ESXi. The other part of the overhead comes from the number of vCPUs and amount of RAM.
VMware View 5.0 introduces a 32-bit color depth and makes it the default option. On top of that, to allow 3D support, VMware introduced a new feature in View 5.0 that allows administrators to select how much video RAM should be assigned to virtual desktops.
The following screenshot shows the configuration of vRAM for vDesktops requiring 3D capabilities:
The VMware View explanation of how to configure vRAM for 3D support is not very helpful and essentially says that more the vRAM, the more the 3D performance available to vDesktop(s).