I get these aren't gaming focused CPUs but if I skipped over the games I can't imagine it would go down to well with many of you, so I've picked four CPU-intensive games that do as good a job as any of utilizing cores. That said, most are best handled by a 6-core/12-thread CPU. Battlefield 1 for example still hits the highest frame rates on the Core i7-7700K -- still, for a core-heavy CPU the 7900X performs great, and so did the 7820X and 7800X.
Mafia III was one of the few games that really took advantage of Ryzen when it was first released, allowing AMD to enjoy strong gains over the 7700K in this title. However, the game was quickly patched to either become less CPU intensive or better optimized, I'm not sure, but the direct result was lower CPU utilization while achieving slightly better frame rates. Here we see that the game still favors the higher clocked 7700K but also still requires more than four threads as the 7600K is quite a long way down our graph.
Hitman is a surprisingly CPU demanding title. Please note I've tested using DirectX 11 to avoid the issues Nvidia GPUs seem to have with Ryzen when using DX12, though I haven't revisited this recently. Anyway, the Skylake-X CPUs perform well, though again it's the 7700K that's the fastest option here.
Finally, we have Ashes of the Singularity, the only game that can really take advantage of 10-core CPUs, though at this point it's more of a synthetic benchmark than a game anyone actually plays. Nonetheless, it give us an idea of what future games might require, though how far away that future is anyone's guess.