Here, the 6950 XT is at various prices but the 4070 Ti is at about $200 more - for the cheapest models - so your observations appear to be accurate. My psu is 850W is probably enough but I still think your point was made. The AMD 6000 cards are not very efficient although these are the higher tier cards - the 3080 Ti/3090/3090 Ti cards are not exactly power efficient. However, I think some good 850W models are sufficient for a 6950 XT or 3090, though? The concern, as I understand it - are the 'transient spikes' that the 6950 XT is said to do? Edit: the 3080, 3090 and 6950 XT are known to occasionally have transient spikes which would make a 850W a safe recommendation instead of anything lower?I do if it means having to spend another $200+ on a good PSU, and then having to go through the hassle of replacing my old one, cable management, etc.
For people running on 600W-750W power supplies-the 6950XT is a basically a no-go, and that $200+ difference on top of the GPU all of a sudden puts the 6950XT at 4070Ti prices, with less performance. At that point just get a 4070Ti and save yourself the headache that comes with swapping out a power supply.