Yes and no. There is sharing of RAM with IGPs from AMD and Intel, but my understanding is the way Microsoft handles the RAM sharing isn't quite as 'unified' as with MacOS. It's not a difference in hardware really, but a software implementation. Also, when we're talking about older Intel/AMD IGP solutions, the graphics cards paired really couldn't take advantage of larger amounts of RAM.
Something like the new Strix Halo stuff from AMD is actually useful with larger amounts of RAM, and basically is the same as the Apple architecture.
Something like the new Strix Halo stuff from AMD is actually useful with larger amounts of RAM, and basically is the same as the Apple architecture.