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In the Presets menu at the top of the window, there are sampling presets for draft, production, etc. Furthermore, you can save your own sampling presets there.
Alternatively you can use the presets for parameters noted by the triple bar icon next to the parameter name.
Presets for parameters can be accessed like this:
IPR Samples
The IPR samples provides a separate Max Samples and Pixel Variance for IPR rendering. By default, this is set lower than render settings for quick feedback.
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