The 5xx chipset is a joke. The b550 pulls all its pcie 4 support from the cpu not the chipset. No reason that if a b550 chipset can gain from the pairing that an B450 or X470 can't other than AMD wants to make you buy a new board. I am pretty much betting though that this extra performance ends up not amounting to much when real 3 parties put it to the test.
AMD have a long way to go to be competitive to Nvidia in GPU.
There is also Blender and Compute and Linux and Driver stability and Ray Tracing feature support and GeForce Experience features...
However I was surprised a little by the RX6900XT.
I thought they would produce a card to be around or slightly lower than RTX3080 performance if they were just using GDDR6.
I thought they would need HBM2e to solidly beat an RTX3080.
It looks like they have a combination of "Infinity Cache" + GDDR6 instead of HBM2e.
The Smartt Access Memory feature that works only with RX6000 series GPU could be seen as against AMD usual "Open Standards" message if they do not open up that interface to Nvidia and Intel though.
I need to see more technical details about the Smart Access Memory feature but sure if no reason why not work on earlier Ryzen board then it should.
Might need PCIe 4.0 speeds though.
Another reason for better than espected performance.
These AMD reference designs are > 2 slot ...
RX6900XT = 2.5 slot.
RX6800XT = 2.5 slot.
RX6800 = 2.0 slot.
The 6900XT makes no sense to me.
It will likely only be ~ 3% faster than RX6800XT when also in "Rage Mode" and "Smart Access Memory" on.
There is no reason 4xx boards can't support pcie 4 other than AMD doesn't want them to. Again B550 pcie 4 support comes from the Ryzen CPU not the chipset, unlike x570. So unless the reason is anything other then it is a feature none of us know about on any of the boards and I do doubt that exists.
6800 xt pricing makes good sense but not the non xt ,more sense if 6800 were priced like the 3070.
I can't really argue the 6900 price wise as by comparison it is a deal compared to the 3090. However if you ask me even 999 is way to much for a GPU. I am sure plenty will buy. However I do think there are more cheap skates like me out there that think these are all priced too high.
Looks very probable Nvidia is going to rework their line up. With release still a little off. There is still time for pricing to change. I just don't get why AMD would not price that 6800 the same as the 3070. In raw performance it isn't that much faster than the 3070. In fact not much different than the 5700xt is than a 2070 super. Yet the 2070 super was the all around bang for the buck card last round. AMD is missing the boat on the 6800 being that this time around.