Question RX 5000 Cards @ PCIe4 x8 in Practice: Freeing up PCIe4 Lanes

[icedamascus]

I see a lot of posts here and elsewhere theorizing about dialing down a Radeon RX 5000 video card on an X570 board to PCIe4 x8 rates in order to free up lanes to allow additional PCIe4 devices to concurrently operate at their native PCIe4 rates unrestricted. But it's more difficult to find posts expressing people's actual familiarity in that pursuit.

What are folks' experiences who have actually put this practice into motion within their X570 systems, especially those where their vid card is installed in the x16 slot? Were there unforeseen hardware and/or software barriers that prevented them from initially getting such a system to recognize, respond and run as desired?

The background context to these questions is my considering to put an existing 5700 XT into an X570 build such that more lanes are available for other PCIe4 devices in order to potentially run at their max rates. I'm just trying to look ahead and leave certain upgrade options available.

Thank you in advance.

 

[kanewolf]

I see a lot of posts here and elsewhere theorizing about dialing down a Radeon RX 5000 video card on an X570 board to PCIe4 x8 rates in order to free up lanes to allow additional PCIe4 devices to concurrently operate at their native PCIe4 rates unrestricted. But it's more difficult to find posts expressing people's actual familiarity in that pursuit.

What are folks' experiences who have actually put this practice into motion within their X570 systems, especially those where their vid card is installed in the x16 slot? Were there unforeseen hardware and/or software barriers that prevented them from initially getting such a system to recognize, respond and run as desired?

The background context to these questions is my considering to put an existing 5700 XT into an X570 build such that more lanes are available for other PCIe4 devices in order to potentially run at their max rates. I'm just trying to look ahead and leave certain upgrade options available.

Thank you in advance.

Other than PCIe 4.0 SSD, what "devices" do you have that need PCIe lanes?

 

[icedamascus]

SSDs, possibly in RAID, are the only things I'm looking into at the moment. The potential mixture of m.2 socket and PCIe slotted devices are where my research is currently focused. The freeing up of PCIe4 lanes for other future devices, that make use of those data rates, would be more of future prepping consideration.

Mostly wondering whether dropping down an Rx 5000 video card will allow for the bios/system to either automatically allocate those freed PCIe4 lanes to devices that can utilize them (say, bumping an PCIe4 x4 rated SSD operating at x2 up to x4), or at the very least allow me to manually allocate them? Would that be a pretty straight forward process?

I'll admit that I may be overthinking this, but I like to have a relatively good idea of what to expect before venturing into a new build that utilizes a newer generation of tech.

Thanks again.