1,000% CPU utilization in Astro Pixel Processor. I'm three hours into processing this stack of 720 luminance images for M101. It's currently 29% in writing the light stacked image. So I anticipate about 4 hours total to stack this set. Interestingly CPU utilization isn't maxed. This iMac Pro has 32GB RAM, and 8 cores clocked at 3.2 GHz.