I'd expect the 3600 to be faster due to higher clock speeds,as the TDP limit for 4600G includes the iGPU; if you intend to purchase a discrete GPU anyway for gaming, the 4600G over a 3600 becomes dubious...
(remember, the 4600G is not the upcoming 4th gen proces despite it's name, but is instead essentially a slightly detuned/ slower 3600 with integrated graphics...)