Like many ThinkPads, the ThinkPad Twist features Active Protection System (APS) that protects your data by parking the heads on the hard disk (for models equipped with rotating media drives like the 320GB or 500GB models) when it detects sudden movement or an impact. (Twist is also known as S230u)
APS could be triggered while the system is being handled in tablet mode, causing the drive to pause, resulting in a slight delay (several seconds). This operation could cause a lag in image rotation.
By default, APS is set to the highest level of sensitivity to provide maximum protection to the drive and your data. If you wish to adjust the sensitivity, you can do so by accessing the Lenovo APS control panel under the configuration tab.
Simply move the sensitivity slider to the left. This should reduce any lags in display or operation while handling the system .