Neither, both, depends on the game. For games like WoW and other mmorpgs with heavy cpu demand server drops, the 1600 will fare better, having the extra resources to handle the loads. For other, more simple thread games the higher IPC of the Intel is king.
At 1080p the 8400 averages @2fps max, 5fps min higher fps than a 1600 at 4GHz, but that's using the same ram. Using 3200 not 2400 for the Ryzen will reverse those numbers at OC values, but the chances of you being able to tell the difference side by side are 0%
For all intents and purposes, overall, they are the same cpu, so the better cpu will be the one that gets the cheaper platform, including ram and mobo.