Recording Delay slider: Delays the recording of audio by a certain fixed value, helping you to compensate for any delays that are caused by the audio driver.
Note: You should not normally need to touch this setting.
Processing Threads pop-up menu: Choose the maximum number of processing threads used, or have the number of threads set automatically. Automatic is the default setting, and is recommended except when you use other CPU-intensive applications simultaneously with Logic Pro.
Process Buffer Range pop-up menu: Determines the size of the buffer used to compute mixes and effects. You can choose between Small, Medium, and Large buffer sizes.
Multithreading pop-up menu: Determines whether multithreading is set for playback tracks only, or for playback and live tracks.
Summing pop-up menu: Determines whether the Logic audio engine uses double precision or standard precision buffers when summing audio.
Download the guides:
Logic Pro User Guide: PDF
Logic Pro Effects: PDF