How many threads does UE4 use on it's own?

I’m debating whether I should get an i5 or a low end hyper-threaded xeon. I’m leaning towards the xeon cause i do more than just gaming, but UE4’s thread use will effect my decision. I’m thinking games of the future will use more than 4 threads due to both consoles providing 8 CPUs, so leaning towards the Xeon e3-1230v3 (although I mostly care about compile times and getting to play with the Intel compiler, a gpuless I7 equivalent wouldn’t be a limiting factor in gaming anyway, and integrated graphics are worthless). I’m going Intel over AMD because I want to buy/install OSX (non-pirate hackintosh) and use it as a testing platform for mac builds as well. I also like that xeons life expectancies are measured in decades, and Intel runs cooler than AMD (which is what caused the chain of events leading to my AMD procs death, even if it’s my fault).

Getting off topic, I fried my Phenom II last night during a cleaning, but it’s turning out to be a good excuse to get a long overdue upgrade. Anyway, i know thread-use can be game-sensitive and depends on more than just UE4, but how many does the engine use on it’s own?

On further inspection, I can see UE4 spawns quite a handfull of different threads, glad to see my i7 is being put to use.