So been playing around with explict Mgpu with direct X 12 since my other 5700 XT came back from RMA. Just ran this last one a few minutes ago not my best graphics score but my average. Driver is 19.9.3 SCORE 15 473 with AMD Radeon RX 5700 XT(1x) and AMD Ryzen 7 2700X Graphics Score 17525 CPU Score 9303 Timespy only picks it up as a single gpu. This is why am showing radeon settings so you can see it is enabled. Yes you have to enable "crossfire" for multi gpu on dx12 to work.