Yes, Threadripper 3s can handle dual-CPU setups.
Yes, Threadripper 3s can handle dual-CPU setups.
Certain Epyc CPUs have parts that work when turned into Threadrippers, while others have sections removed.
They don't work on EPYCs. The same applies to Intel, HEDT i7s and Xeons—often they share the same motherboards, but an i7 (or newer i9) can't support dual socket setups. You'll need a processor with dual (or even quad) QPI connections, which some Xeons have, though a few remain single CPU only. A compatible motherboard with the server chipset is also required.
All the options seem to be designed for just two processors, not more. Only certain models like Epyc allow this setup, and they limit it to two at a time.