explanation of memory usage in vsphere virtual centre

Actully the ballown driver is consuming the memory, Ballown driver is the Memory management technology , by default it was enable it was taken the unused memory from the another guest VM and given to the respective Guest VM, that is the reason it is showing more memory, and also you need to check the resource pool also,Ballown drive is doing all those things

In Task Manager VMware will baloon the memory with zeroes and this will allow it use that memory on other VMs.    When the need arises it will give that memory back to the VMa as needed.

300MB is being used by vmware outside of the VM for overhead, etc..

So what unit tells me exactly how much the vm is using

The 94MB is used by the VM, 300MB is used by the VM and ESX host (total ESX host resources).  The information in task manager is useless in most cases, use the performance tab on the VM in the VI Client to get a good guage of what the VM is doing

so how come i have a vm on a host that the active memory of the vm is 550mb and the consumed host memory is nearly 4gig

I have seen this and usually indicates that the processes inside the VM are trying to hold on to that much memory such as Exchange, SQL that don't actually use it but grab it to make it available.

can it be fixed

thanks