Soldered LPDDR5 saves about 2-3 watts over socketed DDR5.

Yes, there’s a real difference, but it’s not massive. Under load you’ll see LPDDR5 draw roughly 2-3W less per stick. At idle it’s more like 0.5-1W.

The reasons are boring but real: LPDDR5 runs at a lower voltage (1.1V vs 1.25V) and the soldered connection eliminates the power overhead from the DIMM slot and longer PCB traces. Socketed DDR5 also has to drive extra capacitance from the slot itself. It all adds up to a few watts.

For a 15W ultrabook, that’s noticeable — maybe an extra 30-60 minutes of battery life. For a gaming laptop that’s already sipping 150W, you won’t feel it.

If battery life is your priority, LPDDR5 wins. If you want upgradeability down the road, take the small