Even a corsair H60 can run that 9900k at allcore turbo.
What are your SA and IO voltages? System Agent and VCCIO help to run higher speed ram and core clocks.
If you have adaptive or offset voltages with "auto" settings, these can CERTAINLY blast the chip with high voltage and cause overheating.
Id suggest going into the BIOS, and ticking "load optimized defaults". Reboot back into the bios, look at the voltage and temperature monitoring in the BIOS, and set your voltages that you can see, manually. Most likely, the vcore voltage will be very low, so set a temporary 1.25 volts and save settings and exit.
Boot into windows, and use an older program called "intel burn test". you will see it on majorgeek as a download, should say Agent GOD somewhere around it.
Start with the standard 1024mb test. Run it for 100 runs. This should allow you to CREEP onto a high load temp, if it still is the case.
If after 100 runs of only using 1gb, try jumping right to the "very high" 4096mb, which isnt all that high nowadays, when everyone and their momma has 8 or 16gb of ram.
If you still get odd temps, a re-paste may need to be done.
The 9xxx series of intel chips are sometimes plagued with concave chip covers (IHS), and may need a bit more thermal paste than usual. If using a non-conductive paste, throw a little more than normal on there, and use a little extra pressure when tightening the chip down. Still be careful/mindful of stripping threads though