It would also largely depend on the software. Multicore vs multi cpu are not the same thing. If the program isn't coded to take advantage of a multi cpu setup like a workstation/server board with 2-4 cpu sockets on the same board then the program will run off just one of the single core cpu's. Very little software is written that way, to be able to address separate physical chips. A single multicore cpu will almost always give more performance.
Looking at something like a pentium g3258 with core speeds of 3.2ghz, having two of these vs a single i5 like a 4690k has no advantage. Granted the g3258 is a dual core but even if it were a single core cpu, the i5 has core speeds as high or higher and twice as many. Literally twice the hardware...