cheapest motherboard with 4 pcie slots: Các chuẩn kích thước mainboard thông dụng nhất hiện nay. What Should to Do With Extra PCIe Slots?. Echo Express SE I (Thunderbolt 2 to PCIe Card Expansion System ... .
HDMI-compatible/VGA/NVME M.2 B75-MS Motherboard Max Capacity 16GB LGA 1155 Motherboard Supports 2 Memory
Slots Mainboard with PCIe 16x for PC Gaming.
So I think the final answer is ASUS Corsshair Hero/Extreme as a motherboard with
4 slot space between
PCIe slots and x8/x8 support of PCIe 4.0.
PCIe 3.0 protocol standard: 4 PCIE slots include 2
PCIE X16 slots, 1 PCIE X4
slot and 1
PCIE X1 slot. The X99 motherboard supports the PCIe 3.0 protocol.