We recently set up a generic test Win 2K8 guest instance on an ESX server . The client was given 12 GB ram ( the host has 26 ) . In the VM , in windows task manager it claims it 's using 1.75 GB ram . On the ESX server , it 's claiming this VM is taking up 7.7 GB of host RAM however ( compared to the 10 or so Win 2K3 instances that are only about 1 GB ) .

Question: What may be the reason why they are getting different readings ?
Answer: Because they are on different programs .Because they are not doing a fair assessment .Because they are on different servers .Because they are trying to prove how horrible microsoft is .