Which is better, two 8GB and one 16GB?

It is not always true to say that two is better. Because it has become a short question that can not be answered. RAM motherboards have dual channel and single channel. One ram can not be counted as a channel. A single channel has only one channel that works directly with the CPU, while a dual channel has two channels that have twice the bandwidth and are faster than a single channel. That is why it is said that two are better than one.

But as I said at the beginning, this is not always the case. Some laptops only have a single channel. You can install two RAMs, but it does not matter if it is a single channel. Most desktops are clear, but it is easy to say that dual channel is better if it is not the older generation. Laptops still use single channels in the latest generation.

This means that since mobile CPUs and mobile GPUs are not as powerful as desktops, if a channel is routed for dual channel bandwidth, one more current will flow through the PCB, and more data will be needed on the PCB.

But it has never been fully utilized. On laptops, the CPU and GPU are fixed to the PCB, and the PCB is small so there is not much traffic. Laptops are no longer used by the makers of laptops if they are all compact and will not be noticeable even if they are dual channel. Because it is not enough to run out and get back.