This is the official xmrig benchmark site, all tests there are done online and validated on the server. What you see in the table at the top is an overclocked and highly tuned CPU (i.e. consider it competitive benchmarking), probably water cooled and with tweaked memory. 18-19 kh/s for 5950X is actually low, it can easily do 20-21 kh/s with just a bit of tuning.
Do you consider the AMD CPU Ryzen 7 5800X3D hashrate of 17.75 kH/s as listed on nicehash.com to be fake?
I don't have a chance to check because I think CPU mining is pointless at the moment. And one processor needs a lot of hardware.