I'm upgrading to the 7640u main board and need to buy some DDR5 sticks to go with it. The general wisdom seems to be that it's important to get RAM with the maximum supported speed of 5600MT/s to maximize the CPU/iGPU performance. However, I can't seem to find any numbers on how much of a difference it makes.
The cheapest 4800MT/s set is ~40% cheaper than cheapest 5600MT/s set I can buy right now, so if it's only a few percent, I'd rather save the cash.