432108a5_poly__Reference__Description
[Name] parallel [Type] int [Description] 
Toggles parallel processing. When this attribute is set to enable parallel processing, the poly~ object enables the use of multiple threads to run audio processing for all patcher instances. Otherwise, poly~ runs all patcher instances in the audio processing thread. The DSP chain must be restarted whenever the parallel attribute is changed. This attribute is disabled it when Max is hosted by the Live application. Note: At this time, you cannot specify a single subpatcher on a different core. When enabled, this attribute splits up the number of voices between the number of processors available. It is primarily intended for patches that use a significant amount of CPU within multiple voices of the same poly~ object, and the multithreading overhead is primarily useful for larger signal vector sizes (at least 32 or greater). Other situations will not benefit. Using the default threadcount (which is equal to the number of physical cores) is best."
poly~ Reference