Define "easy". The main problem is the exponentially rising power consumption, because the CPU goes beyond the limit of efficiency at stock already.
I've read many reviews of the 11900K and they all concluded that OC is pretty much poinless. Let me quote a few interesting observations:
We review Intel's new Desktop flagship processor, the 8-core Core i9-11900K. The 11th generation Intel Core desktop processors previously known as RKL aka Rocket Lake-S has been released in an effort to take on the battle with AMD. Overclocking
www.guru3d.com
"As always we tried to overclock the processor. It certainly is doable but we're not sure if it is desired; proper liquid cooling is a must with this processor series. We got the processor stable at 5200 MHz all-core. 5300 MHz would boot fine, however created too many stability issues. At that point, we'd pass 1.5 Volts on the CPU. The heat production is significant. Realistically I'd say, leave tweaking for what it is as the defaults of these processors are already really close towards these performance regions.
5100 MHz all core yields 380W power consumption (system / GPU inactive)
5200 MHz all core yields 410W power consumption (system / GPU inactive)"
The Rocket fails to ignite.
hexus.net
"Rocket Lake-S requires plenty of juice at the MCE-optimised frequencies run for the benchmarks on the previous pages. Overclocking by running the highest all-core speed at a set 1.4V gave us a final frequency of 5.1GHz, which is lower than what the chip boosts to on fewer cores.
You may ask the question as to why bother? This all-core 5.1GHz speed is the same as the supposed frequency the chip runs at with Adaptive Boost Technology enabled, while CPU-only power consumption rises to around 300W and puts our impressive Noctua cooler under tremendous pressure. The differences are minor, insofar as manually overclocking guarantees the frequency is applied at all times, not just when ambient conditions are correct.
Running all-core this way, the low-load PiFast result is actually slower.
Multi-thread benchmarks show a small gain in performance, intimating it's not really worth overclocking as one increases the chances of failure without a decent reduction in rendering time."
11th Gen Rocket Lake CPUs mark the first shift in architecture for Intel's desktop line-up since Sky
www.kitguru.net
"The real jaw-dropper comes when you enable Adaptive Boost and watch the all-core speed push to 5.0GHz or 5.1GHz. The bad news is the five or six percent increase in clock speed requires 25 percent more power. These figures suggest that Intel has felt obliged to push way beyond the point of efficiency in a desperate scramble for clock speed and performance."
The Intel Core i9-11900K is the company's Rocket Lake flagship. It uses the new Cypress Cove architecture and includes support for new instruction sets like AVX512 and DLBoost to speed up AI calculations. We run the processor through our new test suite and also take a closer look at gaming...
www.techpowerup.com
"Overclocking was really a tough nut on the Core i9-11900K. While I could boot at 5.1 GHz, it never was stable, not even with 1.5 V. So I settled for 5 GHz, which was easy enough, with just 1.4 V.
Unfortunately, this means that there really is no point to manual overclocking. Just increasing the power limit will yield you better performance while offering perfect stability. Also, Adaptive Boost can work on top of that."
Intel Core i9-11900K 11th Gen Core Desktop Rocket Lake CPU Tested, Adaptive Boost On and Off, lots of benchmarks, and games, 1080p and 4K.
www.thefpsreview.com
"Turning on Adaptive Boost increases the CPU Package Power by a whopping 28%. Now, we in no way shape, or form saw a 28% uplift in performance. Therefore the power demand for the small percentage in performance we got across the board in our benchmarks is completely and wholly inefficient, and just quite insane to be honest."
Conclusion: Not worth it. ABT (Adaptive Boost Technology) is basically doing the overclocking for you, with already only little gains for a lot more power consumption. You won't get far beyond that. So just remove the power limits in the BIOS, enable ABT if you want, and hope that your cooling can handle it.