Will my graphics card work in all PCIe slots?

Why Asus Pro WS X570-ACE not working with 3 GPUs? Code 43 pcie 4 gpu in pcie 3 slot Every desktop PC motherboard has a number of PCIe slots you can use to add GPUs , RAID cards, Wi-Fi cards or pcie 8x slot GPUs PCIe slots and still can't make them both use x16 Using GPU-Z, I found the following: - GPU-1 : supports x16 , using x4

pcie 40 in pcie 30 slot PCIe x16: This is the largest PCIe slot with 16 data lanes PCIe x16 slots are associated with graphics cards and provide the highest bandwidth available