Edit>Preference>Priority>Snapshots>Take and restore snapshots in the background
を無効にする。
http://www.vmware.com/support/ws55/doc/ws_learning_prefs_priority.html
If you select Take and restore snapshots in the background, you can continue using your virtual machine even when Workstation is taking or restoring a snapshot. Enabling background snapshots for a host with slow hard disks may affect performance. If you experience significant performance problems when taking or restoring snapshots, turn off this option.
Workstation supports only one background snapshot process at a time for a virtual machine. If you take or restore a second snapshot before a previous snapshot operation completes for the same virtual machine, Workstation displays a progress bar until the previous snapshot operation completes. Then the second snapshot operation continues in the background.
A virtual machine that is powered on does not recognize any change to this check box until you restart that virtual machine.
Disk性能に引っ張られる事が少なくなる。
