Hello ollie,
Thank you for your post.
Please let us know the "MediaInfo" data of the file you are trying to edit. You need to have MediaInfo on your computer (you can download it
here )
You can send us this information to support(at)solveigmm(dot)com.
The CPU consumption depends on the input file characteristics.
If you open HD, Full HD or Ultra HD video then the CPU usage can increase.
Please check the file, if the resolution with MediaInfo - if your file is of 1280x720 or 1920x1080 or 3840x2160 then the editing of this file can take more CPU usage.
Regrettably nothing could be done with CPU if the file has such resolution.