Update 10/26/2010 Hyper-V with Service Pack 1 Beta
Update: Release Candidate em 10/26/2010: http://www.microsoft.com/windowsserver2008/en/us/sp1.aspx
Today I managed to install the Service Pack Beta 1 of Windows Server 2008 R2 and found it very interesting changes in hyper-V (Dynamic Memory), as was already announced (SP1 Windows Server 2008 R2 and Windows 7 SP1 is available in Beta 1).
As can be seen in the picture above, you can choose static memory (fixed) or dynamic.
The interesting are the possibilities to indicate how much memory will be incremented based machine priority over other virtual machines (VM) on the same server. In slider Memory Priority you indicate as the machines to be initialized may allocate memory of Hyper-V.
NOTE: IT IS important to stress that the memory be dynamic RUNNING the VMs running Windows 2008 R2 and Windows 7 are also with the SP1 Beta. In other VMs machines mostly self-configuring memory as they are being initiated.