Ryzen 3900X (and probably 3950X) would agressively limit all core boost to fit in the TDP. A Threadripper with a higher TDP limit (and better cooling) will be

Ryzen 3900X (and probably 3950X) would agressively limit all core boost to fit in the TDP. A Threadripper with a higher TDP limit (and better cooling) will be able to boost all core to same levels as single core, ideal for workstation workloads. Some of that TDP is also spent on driving additional memory channels and PCIE 4.0 lanes. There were rumors of TR having 8 channels now. And judging from active cooling on X570 chipsets, PCIE 4.0 is hot.