Overclocking on the Z590 platform is pretty much the same as what we saw on Z490. You will notice, at least with the Core i9-11900K that you are not going to be able to get a whole lot more out of these chips. I decided to do all of my overclocking using the Intel Extreme Tuning Utility. First we run the Intel Speed Optimizer, which is basically like an instant overclocking tool. It puts our all-core frequency at 5.0 GHz.
Running the built-in stress test we could see that the all-core overclock was stable, although temperatures were pretty high.
Going into the Advanced Tuning section we can further adjust the core ratios. After much testing we were able to achieve a stable overclock of 5.1 GHz (51x). We could easily boot the system at both 5.2 GHz and 5.3 GHz (all core), but the system was not stable.
Running the CPU stress test it passed, but our temperatures were quite hot, so that is something you might want to keep an eye on.