The reason you need more cores is because a daw is really a series of single threaded applications. Each track and it's plugins go on a singkr core until you run out. A track is one point of process, so for my description, a bus serving multiple console tracks would be on one core, as would the tracks feeding it.

The more cores you have, the more you can spread out the processing and create efficiencies.

I guess ram would play a role here too, but cores are really the key.