The 3960X would be better, while they would have the biggest benefit for multi-threaded operations like light building, the 3960X also has a higher clock speed so it should be a bit faster for single-threaded operations too
Sorry I meant the 3950X (16 Core) and 3960X (24 core) and t hanks for your response. The price diff is just so huge, only if would make huge difference would i do it