theoretical or real world...
From what we heard from stadia it seems to be about X1X level of power, while this seems to be about double (on raw number, performance will be much higher).
On real world with latency, bandwidth and all else Stadia will be lower than full HD, this will be about 4K (capable of 8K output per the interview).
Stadia is more powerful than XBO X and PS4 Pro combined. That was confirmed by the specs shown at its reveal. I don't know where you heard that it's only XBO X-level, but that's false.
Stadia is also shooting for 4K 60fps at launch, with 8K 60fps as time progressed. I don't really like thrown out numbers like that anyway because it's just unsubstantiated flexing, but that's also something that was said explicitly at reveal. It has as much validity atm as anything confirmed so far for PS5.
I'm really just curious how streaming platforms will compare spec-wise to standalone consoles. The next 3 years will be buy far the most interesting in gaming since maybe the Wii/DS/XB Live era. So transformative with streaming, VR, and new hybrid platforms like Switch entering the mainstream. (pun intended) Considering rumors of PS5 being $500, I wonder if they'll consider selling a cheaper $400/$450 model that's digital only. Exciting times!
Well, this is new.