Questionx16 4.0 Issues
Questionx16 4.0 Issues
I have a 5800X3D, 6800XT, P3 Plus, and AX210 on a B550 Phantom Gaming 4 motherboard. My PCIe speed for the graphics card is x8 4.0 according to gpu-z. I've updated the BIOS, adjusted settings, and even reset the system, but it still won't reach x16.
I also have another PC with the same motherboard but a different setup—5600, AX200, 6750XT—and it runs at x16.
Am I missing something? Is there anyone who can assist me?
I've reviewed some BIOS updates. Please specify the BIOS version currently active.
Your motherboard supports slots M2_1 and M2_3 for storage. Which one are you using?
Is this a wireless adapter filling M2_2 or a PCIe card in a slot on your board?
Even after a full reset, my system still can't reach x16. Could you clarify what you mean by a reset?
Am I missing any details? Do you need assistance?
What is the model, year, and specifications of your power supply unit for the initial build?
Have you attempted to clear the CMOS on your motherboard?
The top model, the 4.0 one, is running in the same unit as my other PC.
It's located in the m.2 E Key slot.
New windows are opening and the BIOS is being reset.
The 6800 XT comes with a HX1200i, purchased used from someone two years ago who hardly used it. The functioning one has some random 750 watt capacity.
CMOS has been cleared.
Attempt to reinstall chipset drivers and then reinstall the GPU. New installations appear. Windows 10 or 11? Make sure you regenerated your bootable USB installer to avoid corruption. Are you installing the OS in offline mode? Since you have identical boards for both builds, try swapping the GPU and moving the PSU between platforms to compare performance or see if x16 speeds are achievable. If results remain unchanged, check the GPU connectors for any damage.
I own a 5800X3D, 6800XT, P3 Plus, and AX210 on a B550 Phantom Gaming 4 motherboard. It might just be lane sharing. If your AX200 is a Wi-Fi card, how are you running the operating system here?
'I have another PC with the same board but a 5600, AX200 and 6750XT, and it runs at x16.'
Look for the difference? No mention of NVMe to host the OS. How does it work then? Do you have a SATA SSD in it?
The wireless adapter uses only one PCI-E lane and wouldn't split the PCI-E 16x 4.0 slot between the NVMe and GPU.
In any case, PCI-E 4.0 8x has no performance difference compared to PCI-E 4.0 16x with this GPU.
Page 3 expansion slots include Ryzen CPUs (Vermeer and Matisse) with two PCI Express x16 slots, and Ryzen APUs (Cezanne, Renoir, Picasso) also featuring two PCI Express x16 slots. The 5800X3D model is labeled Vermeer, and the 6800XT must be placed in the PCIE1 slot. Page 8
PCIE 4.0 bandwidth equals twice the bandwidth of PCIE 3.0. I'm curious if a 6800XT in a PCIE 4.0 slot with 8 lanes would behave like it does in a PCIE 3.0 slot with 16 lanes, determining its operating mode accordingly.
The second PCI-e port only accommodates 4 lanes, which prevents it from supporting 8x or 16x in that slot. This board clearly lacks the number of lanes found in more advanced models. It seems the first PCI-e 1 4.0 16x slot is divided with the first M2 slot, using 4 of the remaining 8 lanes, leaving the other 4 lanes likely unused.
Switching the OS to a SATA SSD and removing the P3 Plus NVMe should display the GPU running at 16x in gpu-z. However, if you use NVMe, all lanes would be returned to the GPU. Performance differences shouldn't be significant. This setup doesn’t appear to have any major issues in the specs, though.
It’s not immediately clear from the details whether there’s a technical flaw, as it might require some decoding and research to confirm.
After purchasing a board that isn’t among the top models, the seller can simply explain that it doesn’t meet expectations.