Certain applications might perform better with more memory available. Having more memory available to the operating system can facilitate caching, which can improve performance of the virtual machine. You can change the amount of virtual memory available to a virtual machine.

For the best balance of performance between Windows and Mac applications, do not give Windows too much memory, because it might cause your Mac to become slower. For Windows XP, 512MB of memory is ideal for Internet and office productivity applications.

For Windows Vista, Windows 7, and Windows 8, 1 GB of memory is ideal for Internet and office productivity applications. This is true for the 32- and 64-bit versions of the Windows 7 and Windows 8. If your Mac has at least 6 GB of memory, Fusion will use 2 GB as the default for 64-bit versions of Windows 7 and 8 guests. These settings are the default memory settings for Windows virtual machines that VMware Fusion Easy Install creates.


Manufacturer recommendations do not generally take virtualization into account in terms of performance. Good performance relies on balancing the needs of the Mac with the needs of the virtual machine.

Shut down or power off the virtual machine. You cannot change the setting while the virtual machine is powered on or suspended.


From the VMware Fusion menu bar, select Window > Virtual Machine Library.


Select a virtual machine and click Settings.


In the Settings window, in the System Settings section, select Processors & Memory.


Set the amount of memory to allocate to the virtual machine by using the slider control.

The memory slider control displays the recommended amount of memory for your virtual machine.