VMware Fusion automatically sets hard disk buffering according to what guest operating system you use, but you can change the setting.

Hard disk buffering can increase performance of your virtual machine. Hard disk buffering can also consume more memory on your Mac host than operating unbuffered. VMware Fusion enables or disables hard disk buffering based on your virtual machine's operating system.

For all Windows Vista and later guest operating systems, VMware Fusion defaults to unbuffered I/O for Mac hosts. The same is true for all Windows 2000, 2003, XP, and XP 64-bit guests newly created with this version of VMware Fusion. All other guests default to buffered I/O on Mac hosts.

If you are not familiar with the options, keep the default setting.

1

Select Virtual Machine > Settings.

2

In the Settings window, select Advanced.

3

Click the pop-up menu for Hard disk buffering and select an option.

Option

Description

Automatic

VMware Fusion determines your operating system and enables or disables hard disk buffering depending on which is better for performance.

Enabled

Buffered I/O is used for this virtual machine's operating system.

Disabled

Unbuffered I/O is used for this virtual machine's operating system.