Why Blender doesn't use 100% CPU time when baking a smoke simulation?

I recently asked if the Blender’s smoke simulation system is multi-threaded, in essence - will it use all my CPU cores and threads?
The answer was positive. I was told that it’ll make my CPU sweat. Great!

However now I’ve finished my Ryzen 7 Linux build and it looks like Blender’s only using about 20-25% of the total CPU time available when simulating smoke. It’s very slow for this CPU. I wonder where is the bottleneck - is it the speed of my RAM? Or maybe Blender could be optimized to use more CPU power, when it’s available?

Here’s an example screenshot showing Blender baking smoke, and my system load in htop:


What is your experience with baking smoke simulations?

It’s the same for me with the other physics simulations, for example, soft body or fluid. My cpu is an Intel I7 with 6 cores. I’ve asked the same question. The only idea I had is that perhaps there is only one floating point unit and the 6 cores are integer units, but that’s a guess and I really don’t know.

I’m wondering the same thing. I have a 6 core i7 as well and like to play around with fluid simulations. I asked the question somewhere else a while ago when I was thinking about building a monster duel cpu rig and got told that blender will only use up to 8 cores for fluid baking.

With the announcements of monster cpus from both AMD and Intel it would be nice to get the heads up on this topic from people that really know about it - like if/when any progress might be made towards blender using more cpu cores - so we can make good purchasing decisions. I guess the problem is getting the question in front of the right people!