[NAME] , there are a few different options: In my particular case, I didn't consider it was worth the additional $150CAD to go from a non-K to a K CPU. By removing the turbo boost limits and installing a good cooler, my 10900 can maintain turbo boost for as long as I want it to.  Another thing to keep in mind while you make your choice is that, in addition to the CPU itself, Dell also includes a better cooler when you order the K CPU, as well as heatsink on the voltage regulator module on the Motherboard. This heatsink is not included with non-K CPUs, and the CPU cooler included with non-K is also pure garbage (small, loud, can't keep temps under control even under moderate load). Your choice to decide if these additional components are worth the price difference. You can get a good CPU cooler for about $50 US and the VRM heatsink is $5 from Dell. I personally preferred to get the non-K and use that money to buy an aftermarket cooler which is better than any Dell cooler anyway.    
I ordered an XPS 8940 with I7 10 gen processor with a K suffix 3.8 to 5.1 Ma. I planned to overclock to 4.0 to 4.2 for video editing. Also includes a 2 GB NVMe drive on the motherboard. I was told that this board has an H470 chip set and won't support overclocking. I looked up spec for 8940 on the Dell site and it says NVMe is not supported. Is it the H470 chipset and what gives with NVMe support. The quoted drive is Intel Optane
XPS 8940, chipset, overclocking