Data-mining one of MSI's Threadripper 3 BIOSes has revealed tuning options for the many CCDs (a.k.a. chiplets) supported by the new HEDT CPUs. It's hard to tell exactly how these features will work, but it looks like MSI is preparing to enable per-CCD overclocking (alongside per CCX overclocking) and disabling and enabling CCDs.
For the uninitiated, a CCD is a Core Complex Die, which is a chiplet that contains eight Zen 2 cores, split between 2 Core Complexes (or CCXs). Every CPU in AMD's lineup that has more than eight cores uses more than one CCD; Ryzen 9 comes with two, and Threadripper 3000 CPUs have four. The CCD allows AMD to have such high core density per socket.
Overclocking controls for each CCD might appeal to some enthusiasts because some CCDs are bound to be better than others, per the silicon lottery. Some are also bound to be worse than others, so instead of being limited by the overclocking potential of the worst cores on the worst CCD, you could just overclock each CCD to its maximum potential rather than the traditional method of overclocking all cores at once. The same reasoning applies to the seemingly-upcoming per CCX overclocking options.
There are also options to disable and enable CCDs. There doesn't seem to be a real reason to disable a CCD at the moment, but this might change when these CPUs are available and people have had the chance to see what exactly the consequences are for doing so (besides losing cores and thus multi-core performance). Most interestingly, there is a 3 CCD option, which is odd because there aren't any Zen 2 CPUs that use 3 CCDs. At least not yet.
It's unclear whether these features will be available on day one, or if MSI is still working on them. We should ultimately expect these features to arrive at some point, providing a greater amount of flexibility with Threadripper overclocking so you can squeeze out every single MHz possible.