System Configuration : System Setup : Configuring Pro Tools System Settings : System Memory Allocation

System Memory Allocation
(Pro Tools|HD Systems Only)
When you start your computer, Pro Tools automatically reserves a portion of system memory for the Playback Buffer. This reserved memory is unavailable to other applications, even if Pro Tools is not running.
You can set Pro Tools to reserve only the minimum amount of required memory, so that more system memory is available to other applications.
To minimize system memory allocation:
1 Choose Setup > Playback Engine.
2 Select the Minimize System Memory Allocation option.
3 Click OK.
4 Do one of the following:
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On Mac systems, if prompted, enter your password, then restart your computer.
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