You have probably noticed that a great way to test the movements of your IK chain, especially in combination with the Dynamics function of Soft IK, is to press the Play button (or hotkey: F8).
However, since the IK chain works with soft constraints, the animation reacts to a number of different factors. This means that the animation might not be finished at the last frame. The joints might still come to rest slowly. To display those changes without playing back the entire animation, you can use the Auto Redraw command. Once enabled, it will constantly update the calculations, displaying the reactions of your IK chain immediately.
When choosing this command, the dialog will enable you to set the redraw step in milliseconds. If you have activated the Auto Redraw you will find the dialog already below the Object Manager. Normally, the animation will be played back in real-time; for PAL systems, that means 25 frames per second, for NTSC it is 30. Each frame will therefore be displayed for 1/25 or 1/30 of a second before it is updated again.
The default value of 50 milliseconds (20 frames per second) is quite enough to make the movements smooth. Note that each redraw costs processing power. Higher redraw times will cost more processor time. 50 milliseconds is a good average value. Very complex scenes may, however, require faster redraw times.