labels may confuse you since many DDR3 SO-DIMM RAM use frequency (MHz) as their performance metric. Here's a table so you can compare your laptop's DDR3 RAM to the ones being sold in stores ...

DIMM (Dual In-Line Memory Module ... DDR5 memory will not physically slot into a DDR4 or DDR3 memory socket. Within a memory ...

Figure 3: Fly-by Topology for DDR3 Unbuffered DIMM The draw-back to this approach is that the delay from the PHY output signals to each memory is slightly different, depending on where the memory chip ...