VS Render is a free and open source Blender addon for rendering Video Sequencer videos or images. It renders in parts and in parallel, utilising all cores. At this time it works only on Linux. You may need to edit some code to adapt it for Windows.
For more details and to download it, please visit this link on github:
I am not working on a windows version, as I have no usable windows machine here. Probably someone from the community will take up this task, should be easy.
Thanks for the feedback, and as usual I am working on other addons, which are not linux specific.