If you have set it to say 100% then ONLY the tools that honour it will parallelize their operation. It does not parallelize python. You don't really say HOW your rasters are created, so for example if your raster is created from a polygon to raster tool, then studying the environment settings of that tool you will see that it does not honour parallel processing factor.

Suggest you read this help page.

If you have set it to say 100% then ONLY the tools that honour it will parallelize their operation. It does not parallelize python. You don't really say HOW your rasters are created, so for example if your raster is created from a polygon to raster tool, then studying the environment settings of that tool you will see that it does not honour parallel processing factor.

Suggest you read the Parallel processing with Spatial Analyst help page.