As far as I know, Zen+ usually needs quite a lot of tweaking (and ideally, memory @ or below 2666) to get close to Intel idle power and the 1225 has an IGP which (if you're using it) helps even more, but a lot depends on the motherboard and graphics card. It's not that hard to get 30 odd watt idle on Intel systems (prior to 11th gen), even with a graphics card and a bog-standard PSU, but untweaked Ryzen non-APU systems can easily idle at 50+. OEM Intel systems (like Dell, HP, Fujitsu) can run even lower idle, like 15 watt (or less) at the wall isn't uncommon without a DGPU (depends on model).
Performance wise, in productivity tasks that uses the cores, then the 2700X would destroy the Xeon (e.g. cutting the rendering times in half, probably more than that). In older games (made for the quad-core stagnation era), then I don't think you'll notice much, but in newer games I'd expect the 2700X to be quite a lot smoother and more capable than the E3 (since it only has 4 threads and a 3.4 Ghz all-core clock).