So when I render HD or 4K Video with KDENLIVE, parts that have multiple layers, overlays, or where I remove a green screen background... only render at 40% of my CPU's power. I'm using Ubuntu Mate 18.04. When it only uses 40% of my CPU, it takes at least twice as long to render a video. my 4K Videos using the chromakey effect, take 8 hours to render 33 minutes of video.

I have told it to use all my CPU Cores. When rendering a 4K Video track, without any overlays or layers, it renders fast at 100% cpu usage.

If I slide the Encoder Speed all the way to the right, the system often crashes while rendering, so I have it slid over one notch from the right.

Quality is on 15, with audio at 192 when rendering to MP4-H265 (HVEC).

I don't have other issues people have reported about not being able to use clips with different frame rates, or anything like that.
It says my KDENLIVE version is MLT version 6.6.0. Synaptic says it's 4:17.12.3-0ubuntu1 of course amd64.

I will have a video on my YouTube channel tomorrow showing the issue. My video was inspired by "The Linux Gamer" who said that you can't render 4K Video using KDENLIVE.
"The Unboxing Authority" is my YouTube Channel.

I have some ambitious plans regarding KDENLIVE on Linux in the future.

I recently downloaded the most recent Appimage file, and now I get 70% CPU usage with the same conditions. That seems like a big improvement, but I would like to get 100% CPU Utilization.

You can try the following: click render -> click more options -> slider “Encoder speed” to the right, “Threads” change to 2.