It's "compatible" in the sense that it plugs in and runs, but the 32-core processors are going to push the VRMs on all existing boards right to the limit, even at base clocks. After all, it's at least 70% more power than the first gen, and probably higher (most 2000-series Ryzens bust through their official TDP pretty readily).
Turbos are going to be pretty iffy under sustained load, let alone Precision Boost and XFR, which are (iirc) enabled by default.
AMD is shipping all the review kits with an unspecified "add-on VRM cooling kit" to try and help that, and there are second-gen X399 boards coming out with 16 phases (up from 6-8 in the first gen).
Turbos are going to be pretty iffy under sustained load, let alone Precision Boost and XFR, which are (iirc) enabled by default.
https://www.youtube.com/watch?v=aKe7CnZT9ZE
AMD is shipping all the review kits with an unspecified "add-on VRM cooling kit" to try and help that, and there are second-gen X399 boards coming out with 16 phases (up from 6-8 in the first gen).