PCIE Bandwidth

Hi All,

I'm currently working on a VMix build and am planning a Blackmagic Design DeckLink Quad HDMI Recorder inside of it as well as an RTX 4080 super or the equivalent when the RTX 5000 series comes out (availability based). I'm looking to use an X670E motherboard with two direct PCIE slots to the motherboard (ASUS ROG Strix X670E-E) with a Ryzen 9 7900x but am worried due to the fact the CPU only has 24 PCIE 5.0 lanes. I am planning on adding 2 NVMe SSD's (512gb Kingston KC3000 & Crucial P3 Plus 2TB). This system will most likely be running 4x 4K sometime in the future. Will I have a bottleneck and massive performance loss on this board? Hopefully this is the right place to post this.

Thanks in advance.

Having built multiple vMix systems, I'd recommend something with more lanes if you ever want to expand (if it's in the budget).

The biggest issue with consumer boards is that they're not as flexible as workstation/server, granted- they are much cheaper.

Most likely that motherboard uses 4 lanes for the chipset, 4 for the first NVMe drive, and 16 left for the PCIe slots.

You'll notice I didn't mention the second NVMe slot and that's because it often either shares with the chipset or the third PCIe slot.

The 16 lanes for PCIe will often bifurcate meaning it'll run at 16+0 or 8+8 (the most common setup). For what you're trying to do right now that should be adequate. This will even be fine for 4K as long as you can stick to a single DeckLink card in that second slot.

Decklink QUAD HDMI use x8 slot ..

ASUS ROG Strix X670E-E have :

AMD Ryzen™ Desktop Processors
2 x PCIe 5.0 x16 slots (supports x16 or x8/x4 modes)
AMD X670 Chipset
1 x PCIe 4.0 x16 slot (supports x4 mode)


Ryzen slots have configuration :

Screenshot 2025-01-24 at 00.29.32.png (47.22 KiB) Viewed 1198 times

U can put Graphics card here .. But U have not any other 8x port for decklink ..

I doubt I'll use more than one Decklink Card. I will switch to an 8 + 8 configuration for it. Thanks!

Having built multiple vMix systems, I'd recommend something with more lanes if you ever want to expand (if it's in the budget).

The biggest issue with consumer boards is that they're not as flexible as workstation/server, granted- they are much cheaper.

Most likely that motherboard uses 4 lanes for the chipset, 4 for the first NVMe drive, and 16 left for the PCIe slots.

You'll notice I didn't mention the second NVMe slot and that's because it often either shares with the chipset or the third PCIe slot.

The 16 lanes for PCIe will often bifurcate meaning it'll run at 16+0 or 8+8 (the most common setup). For what you're trying to do right now that should be adequate. This will even be fine for 4K as long as you can stick to a single DeckLink card in that second slot.

Instead of this Motherboard would a ASUS ProArt X670E-Creator work. The product page seems to indicate it does 8 + 8 for PCIe Gen 5.0 which should give it enough for both a GPU and Decklink Card.

Decklink QUAD HDMI use x8 slot ..

ASUS ROG Strix X670E-E have :

AMD Ryzen™ Desktop Processors
2 x PCIe 5.0 x16 slots (supports x16 or x8/x4 modes)
AMD X670 Chipset
1 x PCIe 4.0 x16 slot (supports x4 mode)


Ryzen slots have configuration :

Screenshot 2025-01-24 at 00.29.32.png

U can put Graphics card here .. But U have not any other 8x port for decklink ..