http://www.seagate.com/www/en-us/support/downloads/other_downloads/cuda-fw
Barracuda 7200.11 SATA models with firmware SD04 or SD14
A small number of Barracuda 7200.11 drives with firmware versions SD04 or SD14 may show and utilize only part of the available cache. Please follow these steps to ensure that your system recognizes the full cache.
Click here to determine your drive model number electronically.
Below are the Barracuda 7200.11 model numbers. If the orange digit is any number other than those shown, Seagate recommends that you update the firmware on your drive:
Model numbers
1000 GB
ST31000340AS
750 GB
ST3750330AS
500 GB
ST3500320AS
If the drive bears one of the model numbers above then no action is required. If you do have an incorrect model number, please download SeaTools to determine your serial number.
Once you have your serial number contact Seagate Technical Support to receive the AD14 firmware update.