Hi, I'm running a livestreaming studio and looking to expand our setup from currently running one Blackmagic Quad HDMI Capture Card on OBS to increasing the total number of camera up to 8 inputs and upgrading the network to 10GBe.

I was looking at something like:

i9 13900K
RTX 4070ti
64GB RAM
ASUS Z790 ProArt Creator

Until I realised the 3rd PCIe slot is 4.0 x4 but the Quad HDMI Capture Card is 3.0 x8. As I understand it they should be equivalent in bandwidth but not enough lanes.

Does anyone have any advise on a setup that can accommodate this short of spending 3-4 times money on a Threadripper Pro?

Would something like a Sonnet Thunderbolt 3 PCIe Enclosure work?

Thank you for you time!