The difference is quite big:
Reported by $_.ExtensionData.Summary.Quickstats.StaticMemoryEntitlement
Name Host Memory Provisioned MB Host Memory Consumed GB
--------- --------------------------------------------- ---------------------------------------
vm1 2133 0.53
vm2 4339 0.63
vSphere Client UI "Resource Allocation" Tab:
Name Host Memory (MB) Consumed (MB)
----------- ------------------------------ ---------------------
vm1 4329 550.00
vm2 4339 646.00