Comment by kfuse

As I said, traditional doom bsp-walker software renderer is quite parallelizable. You can split the screen vertically into several subscreens and render them separately (does wonders for epic maps). The game logic, or at least most of it, can probably be run in parallel with the rendering.

And I don't think any of the above is necessary. Even according to their graphs popular doom ports can render huge maps at sufficiently high fps on reasonably modern hardware. The goal of this project, as stated in the doomworld thread, is to be able to run epic maps on a potato.