The System Setup Section lets you monitor voice and CPU allocation, and gives you access to some significant settings of your system's audio hardware.
Max. voices = the maximum number of grains that can be generated simultaneously. The higher this setting, the more processing power will be required from your computer. By activating the Mon. checkbox you can see how many voices are currently in use (the Voices meter will begin to move). If you hear clicks or dropouts in the audio and the Voices meter stays mostly to the right, you should set the Max. Voices to a higher value.
Max. CPU% = the maximum amount of your computer's total processing power which can be allocated to RTGS3. The higher this setting, the more processing power will be taken away from other applications so that RTGS3 can generate more grains. Setting this value very high may make other applications on your computer (including Mac OS itself) less responsive to user control.
Clicking the Gear icon opens up the System Setup window:
"Audio Driver" menu = sets which audio driver software will be used by RTGS3 to access your audio hardware device.
"Sample Rate" menu = sets which sample rate RTGS3 uses. Only settings available to your audio hardware device can be used. Selecting a higher sample rate requires more of your computer's processing power.
"Input/Output Latency" menu = sets the delay time (latency) between audio entering your computer's audio hardware device and when that audio is made available to RTGS3. A lower setting decreases this latency, but requires more of your computer's processing power.
"High Priority Mode" menu = when set to "On", priority is given to audio processing operations. On older computers, this may cause other applications (including Mac OS) to become less responsive to user control.
"Driver Setup..." button = clicking this button opens the Mac OS "Audio MIDI Setup" application, where you can make detailed changes to your global audio system settings.