Troubleshooting DIMM Problems

My motherboard has four DIMM slots for RAM They look identical except 1 & 3

Memory modules come in various shapes and sizes, such as DIMM or SO-DIMM, and they contain a series of memory chips that allow a computer to store and access

dimm 2 slot Dual In line Memory Module : The DIMM slots were introduced to cater for multitasking in computing devices

dimm slot PCIe is a newer interface that features a smaller physical footprint, meaning slot on the motherboard