Dear god.
I can't even replicate their Call of Duty 1440p RTX 3090 results (I get higher FPS in multiplayer, and my card doesn't even exceed 350W very much even with a 400W power limit via maxed power slider) because apparently, according to someone else, AMD ran this in "Benchmark mode", however there is no way to activate benchmark mode in the blizzard client. So I guess real end users have no access to benchmark mode. And a +120 core / +600 ram overclock over stock does not give a +30 FPS boost. No way in hell.
Frankly I believe AMD over you. I half kid.
One thing no one seems to be taking into account is AMD lists which API they are using.... and I notice they are sometimes using DX11 when we know there is DX12 available.
But whatever... if you don't believe AMD marketing that is cool everyone takes marketing with a grain of salt. However the current people at AMD are not known to fudge nothing. They don't overlock the NV cards AT all... they also DO NOT overlock their own cards unless they specifically mention they are using one of their Auto overclock features or Rage mode or whatever.
Reviewers will have the cards soon.... and they will test them at stock and tortured. Vs NV at stock and tortured. Then you can compare apples to apples from a third party. I tend to believe you probably really really really overpaid for your 3090. But then most GPUs that are only ever going to be the best of the best for a few months in general are terrible value propositions. Yes if true and the 6900 even trades blows with the 3090, its really going to suck for people that paid a massive premium for a card that was only top of the top for a few weeks. But such is life.
And for the record.... ya the 3090s... seem from all accounts from review sites prone to differences. They are binned chips... and there is a lot more in play then just Mhz they run at. It seems like the quality of the power going to those monstrosities matters and can have real impacts. If you run your card at stock and are besting AMDs results. I would count yourself super lucky, not only did you get one of the apparently couple hundred cards end users have in the wild... you also got one with quality silicon from a supplier that also used quality power delivery components. Congrats. (seriously winning the silicon lottery with GPUs is nothing new and always feels good when you get a card that can clock a little higher and run a little cooler)