For the time being, the highest validated overclock for Intel's brand new Core i9 10900K Comet Lake CPU is just over 7.7GHz, achieved by a team of enthusiasts with tubs of liquid helium at their disposal. Suffice to say, don't try this at home.
Professional overclocker Elmor and his team certainly didn't. Sequestered in a lab at Asus's headquarters, Elmor and the gang got busy dumping a steady supply of liquid helium into a pot attached to an Asus ROG Maximus XII Apex motherboard, which is built for this sort of thing.
The team uploaded a nearly 5-minute highlight video (via HotHardware) showing some of what is involved with these kinds of record overclocking attempts. It's not something to attempt on a whim, and it definitely helps to have the backing of hardware partners—I don't know about Dave or Jacob, but I don't have access to a lab suitable for this sort of thing, let alone tubs of liquid nitrogen and helium.
All 10 cores and 20 threads topped out at precisely 7,707.62MHz, as validated by HWBot, with the voltage set at 1.194V. G.Skill, which is readying a DDR4-5000 memory kit for Comet Lake, was represented as well, by way of an 8GB Trident Z RGB module.
Cool stuff (literally).