You realise this table shows that the 4c/4c i5 6600k is also within 10% of a 10c/20t intel cpu rated to 4.5GHz? So it doesn't really mean a lot. I'd be more intrigued by a comparison of the i5 2500k to the 6600k
i5-2500 will be futher behind. But the real conclusion is that Ryzen is the best buy because you will lose a single or two frames on average but will gain a lot in all other multi-threaded applications. I'd recommend a system with 16 virtual logical processors than just 6 but negligibly faster as per IPC.