Checking Hard Disk Caching Policy in Windows 7

The write-caching policy for hard drives in Windows 7 is enabled by default. Although, this improves the overall performance of the system, if there is a power failure and the system has no backup power such as, an UPS (Uninterruptable Power Supply) data waiting in cache will be lost!

Windows 7 employs cache flushing. This means that the system will periodically instruct the storage device to transfer all data waiting in the cache to the principal storage media. When you select Turn off Windows write-caching buffer flushing on the device, you turn off these periodic commands to transfer the data. Not all devices support all of these features. You find these options in the Policies tab of the device’s Properties dialog box that you access from Device Manager as shown below:

Enabling write caching on a storage device is recommended only when data transfer performance is the main objective and if the system hardware and storage device support these features. On the other hand, it is only logical to avoid these options if you know that your system has known issues with sustaining power.

To verify if your system is having software or hardware problems that are affecting performance you can use the event viewer. The events that would give performance related information are found in the Operational container under Diagnostics-Performance which you access by expanding Microsoft and then Windows in the Event Viewer tree pane.

A shortcut can found in the Control Panel by clicking the Performance Information and Tools item. Click Advanced tools in this dialog box and then click View performance details in event log. This loads the Event Viewer and displays the events in the Operational container as shown below: