Seems like pretty heavily stretched truth. Looks like the actual performance uplift is more like 30%. The 5070=4090 comes from generating multiple fake frames per actual frame and using different versions of DLSS on the cards. Multiple frame generation (required for 5070=4090) increases latency between user input and updated pixels and can also cause artifacts when predictions don't match what the game engine would display.

As always wait for fairer 3rd party reviews that will compare new gen cards to old gen with the same settings.