(Pulling up from child comment) The chip this uses is likely a PM4x100 (x ∈ {0, 1, 2}) from Microchip (formerly Microsemi (formerly PMC-Sierra)): https://www.

(Pulling up from child comment) The chip this uses is likely a PM4x100 (x ∈ {0, 1, 2}) from Microchip (formerly Microsemi (formerly PMC-Sierra)): https://www.microchip.com/en-us/product/PM40100 https://www.microchip.com/en-us/product/PM40100 ^ runs you $800 without bulk discounts [https://www2.mouser.com/ProductDetail/Microchip-Technology-Atmel/PM40100B1-FEI?qs=TuK3vfAjtkVxKfKx2Q%2F8sw%3D%3D https://www2.mouser.com/ProductDetail/Microchip-Technology-A...] — if you can get them, that is. https://www.microchip.com/en-us/product/PM41100 https://www.microchip.com/en-us/product/PM41100 https://www.microchip.com/en-us/product/PM42100 https://www.microchip.com/en-us/product/PM42100 ^ these latter two I don't see publicly listed prices for anywhere. The PCIe 5.0 equivalent is in "Samples available", i.e. not full production yet, which is likely why the card only does PCIe 4.0: https://www.microchip.com/en-us/product/PM50100 https://www.microchip.com/en-us/product/PM50100