Intel Extreme CPUs (LGA 2011 and 2011-3) don't have thermal paste inside, the die and the IHS are SOLDERED together. You can still delid them though with specific tools, and if you replace the solder with liquid metal TIM you can get a much bigger difference than with consumer-grade CPU paste swap (this is because Intel puts way too much solder between the die and the IHS, whereas the paste in consumer grade CPUs ends up as a thin layer). However it'd be much safer and potentially cheaper (1700$ dead CPU is more expensive
) to invest in better cooling. If you can buy an EK Predator AIO (240mm or ideally 360mm) you should be able to even go past 4.4GHz.