You'd need to look at the actual implementation, it's hard to speculate from a tiny amount of data. What game are you referencing?

And as someone who has done multi threaded programming I can tell you that for games it is unlikely that they can just add more cores. You need work that truly can be split up, meaning that each core doesn't needs work to do that doesn't rely on the results from another core

Graphics rendering is easy for this and it's why gpus have a crazy number of cores. But you aren't going to do graphics compute on the cpu