AnandTech went back and retested the i7-2600K against the i7-7700K (Intel's last mainstream quad-core) and for craps and laughs, the i7-9700K: https://www.anandtech.com/show/14043/upgrading-from-an-intel-core-i7-2600k-testing-sandy-bridge-in-2019/4
If you want the tl;dr version in picture form (note the baseline is the i7-2600K at 4.7GHz)