System RAM has no bearing on a GPU

System RAM has no bearing on a GPU in terms of compatibility so no need to concern yourself on that front. Whether your CPU becomes a bottleneck is entirely dependant on what game, video settings and screen resolution you run (however its more GPU dependant than anything else), but given you have a top end last gen. Intel CPU I would not be concerned unless you plan to run 4K resolution and even then a GTX1080 'should' cope.