Parallel Swap File Storage
PixInsight allow to generate several swap storage file per drive (physical or virtual) without specific limit, this way can read/write them through parallel execution threads running concurrently. More information.
The configured units are listed in main preferences in the option Directories and Network (/tmp by default). Press the Add button to add a new unit. Press Remove to remove it. Then save your changes by clicking the Apply Global (blue circle) button.
The performance gain that can be achieved thanks to parallel disk I/O can be spectacular. Try PixInsight Benchmark script to set the best configuration in your machine.
Note: The name and location of the folder is only for reference. Remember that each physical or virutal unit can be selected many times.