Thanks for your reply. But you are wrong, the i5 8500 does NOT bottleneck a Vega 64. In fact, it can even almost max out a 2080 Ti. It's there on YouTube. The GPU usage is always at 100% while the CPU usage is mostly under 50%. That isn't a bottleneck. However, you are right about one thing, obviously if I upgrade my CPU I'd get more FPS in games, but only by a small amount.
That's ebcause it has 6 cores and the benchmarks usually only use 2 or 3. 99% of games still do not use more than 4 cores. 50% means 3 cores at 100%. Which means bottleneck.
If your statement was true, there'd be no reason for gamers to get the 8700K. The 8400 would be declared "budget god of gaming.
However since your claim is actually false and the 8400 is extremely limited by its single threaded performance, why don't you go ahead and run Passmark and post in the CPU sister thread in the CPU forum? We'll see how good your i5 really is.