Ryzen 7 is likely overkill for just a gaming PC if all you plan to do is game. If you plan to do more than gaming like video encoding/CPU streaming, or you plan for the long term on the chance that games will use more than 4 cores, then Ryzen 7 is a fine CPU. Otherwise go with a Ryzen 5 1600 for a fair bit less and 6 cores, or if you want 144Hz gaming, then an i5-7600K overclocked would be better. That's if you plan on pure gaming. It all depends on budget. Since Intel is going to be pushing 6-core chips soon, it also depnds on timing.
The Ryzen CPUs are great, not the best for gaming compared to Intel, but more than adequate, plus you get the extra cores for when things change or you plan to go beyond gaming.
