What Will Happen If You Plug In a DDR3 into a DDR4 Motherboard

Can i use ddr4 ram with another ddr3 ram ddr3 slot Orange Pi 5 Plus（32GB） Rockchip RK3588 8-core 64-bit processor，32GB LPDDR4X, slot supporting SSD and Wi-Fi 6BT module AllWinner H3H5 SoC, 512MB DDR3 ddr3 in ddr4 slot Can I use both in the same computer? Your system is only compatible with DDR4 memory The layout of the pins on a DDR3 modules are

ddr3 vs ddr4 slot DDR3 DDR3 2133 DDR3 1866 ASUS TUF GAMING B650-E WIFI AMD B650 AM5 ATX motherboard, DDR5, 8+2 teamed power stages, PCIe , a PCIe slot