For these past 2 days I've been trying to fine-tune Kdenlive so that it works better for TROM II editing. You see on Linux you won't find a good video editor that's trade-free and uses the GPU. The video card. And without the video card, video editing sucks. Like, totally sucks. Let me give you an analogy:
With a GPU is like having a car. You can go off-road at times, climb hills, drive fast or slow depending on the needs. Without a GPU it is like having a bike. Super slow and at times useless when you have to climb steep hills or go off-road. Video editors on Linux are like having a bike. Some are trying to use the GPU but it is kinda experimental and doesn't work very well. For example Kdenlive uses the GPU (if you set that up in the settings, and do so property for your own graphic card), but when it uses it, it only uses it for here and there scenarios. Like if you apply some effects to a video, those effects cannot be processed with the GPU so it falls back to the CPU. And most effects do not support the GPU. So unless you use no effects in Kdenlvie then sure, it may work ok. Although the timeline preview seems to not use the GPU at all, so good luck for smooth previews if you use 1080p or above footage.
So for now the implementation of GPU use in Kdnelive and pretty much all trade-free editors on Linux, is like putting a motor and a battery on a bike, and inventing the electric bike. That's better since you can go faster, climb steeper hills, and such. But the Kdenlive implementation only works for certain scenarios, so it is like the motor of the ebike only works on paved road and no uphill. That's the perfect analogy.
So for now I will have to use an ebike that only uses its motor for paved and straight paths. It helps a bit, for sure, but not hugely.
Kdenlive has a few tricks to help you with previewing your project in the timeline and such, so for now is fine. But yah....it sucks that I have a GPU with 4GB or RAM and it is barely, if ever, used.
I am hopeful tho that in the next few years the GPU support for video editors will be as good as on the other OSes. Kudos to the Kdenlive team for making a trade-free video editor. That's important for me and I will keep on using it, since it is a great video editor. If it had proper GPU support it would become an amazing video editor.