I may be missing something, but is cycles really this bad at volumetrics?

This is v2.82.7 according to the version number in the corner. I was experimenting with volumetrics for clouds and I noticed my system was universally underutilized. Unless I am making a silly mistake by using cycles rather than eevee, which I know is much faster if with different results, I would have hoped that there would be some other reason my render was this slow than my cpu only using one core at a time.

I’m using OptiX with an RTX 2080 Super. Other details that matter should be visible in the task manager.