whats the difference between PCIEX16 & PCIEX4??

your i5-3470 works on PCIe natively, Optiplex 7010 has only one slot bound to CPU PCIe, others are linked via chipset

EZ-Latch：PCIe x16 Slot with Quick Release Design; Fast Networks： LAN & Wi-Fi 6E ; Extended Connectivity：DP, HDMI, Rear USB-C® 10Gbs, Front

pciex16 slot your i5-3470 works on PCIe natively, Optiplex 7010 has only one slot bound to CPU PCIe, others are linked via chipset

manga slot Notice that the PCIe x16 slot has a retention lever Figure PCIe adapter removal Figure Motherboard with PCIe and PCI slots Tech Tip