x470 Taichi PCIE 4.0

And here is the final say from AMD themselves, from reddit Robert Hallock: "This is an error we are correcting. Pre-X570 boards will not support PCIe Gen 4. There's no guarantee that older motherboards can reliably run the more stringent signaling requirements of Gen4, and we simply cannot have a mix of "yes, no, maybe" in the market for all the older motherboards. The potential for confusion is too high.

When final BIOSes are released for 3rd Gen Ryzen (AGESA 1000+), Gen4 will not be an option anymore. We wish we could've enabled this backwards, but the risk is too great."

https://www.reddit.com/r/Amd/comments/buydi6/amds_robert_hallock_no_pcie_40_support_on_300_and/eplj20j/

So that's that. :D I'm fine with that. On another note I just seen the x470 get a new BIOS v3.43 Ryzen 3000 support and Enhance AMD XFR 2.0 function; change AMD PBO rule with Pinnacle CPU.
Support SMT mode disable.

Yes I agree. After reading many threads on PCIE 3.0 with graphics cards, they barely even use all the bandwidth of PCIE 3.0, unless maybe with 2 GPUS running in SLI at 4K with say 2 RTX 2080ti's or higher. If your using 1 GPU now or in the future, we are all fine for I would guess maybe for 2-3 years more before we see games demand more bandwidth from PCIE. For now it's all about storage. I read that PCIE 4.0 can hit 5,000 MB/s. I'm more than fine with my 512GB 970 Pro. I get 3,566 MB/s read & 2,330 MB/s write. No point to upgrade for 1.5GB more bandwidth that would be a waste of $$. I'm happy I can just buy the 3800x and drop it in my x470 ^_^

I have to be honest, I am not dissapointed that PCIe 4.0 will be restricted to 500 series chipset boards. AMD's track record hasn't been smooth as it is, throw in a new PCIe standard on boards that were not designed for it and you are asking for headaches. The key problem is that AMD don't design the boards and board partners can't predict what will be coming in a generation or 2. Don't get me wrong, AMD are doing a great job shaking up the market but they have teething problems to iron out. Intel have had a lot longer and a lot more budget to iron out their launch cycle. When you consider that Intel's architecture is largely unchanged since Sandy Bridge it becomes clear why AMD, on it's relatively new Zen platform, has some catching up to do.

PCIe 4.0 at present only benefits high bandwidth applications and as it stands, the only practical application is with storage. On the GPU front, PCIe 4.0 is overkill in the extreme right now in all but one way; a x1 PCIe 4.0 slot will be equivalent in bandwidth to an x4 PCIe 2.0 slot where it comes to bandwidth. In theory that could mean we might see SFF GPUs on x1 PCIe slots, all the way up to about the performance of a GTX 1650 before bandwidth bottlenecks make it impractical. If x2 slots (or at least x2 wired slots) become a thing that could go even further. Once we start seeing low tier 500 series chipsets I could see the SFF market exploding with options.

To be honest I don't see this as a big deal. PCIe 4.0 does very little to help current PCIe add-in cards, even GPU's. IMO the main benefit at least in the medium term will be more bandwidth to the chipset, so that the chipset can feed more ports of all types without saturating the link back to the CPU. I'd be surprised if the X470 chipset has the ability to talk 4.0, or the excess capacity to make use of it.

(I suppose that PCIe 4.0 to NVMe SSD's is another potential benefit, and that would be nice, except that transfer time isn't the overwhelming majority of total time that it is in the HDD world.)

no support for pci 4.0 on x470 and earlier.

https://www.sweclockers.com/nyhet/27653-amd-klipper-pci-express-4-0-stod-for-aldre-moderkort-i-400-och-300-serien