What disadvantages does a notebook without dual channel have?

I'm interested in one of the following laptops, but I realize that they each have only one memory module. What are the disadvantages for me, or for which applications?

Lenovo Ideapad L340-17IRH Gaming Black, Core i7-9750H, 16GB RAM, 1TB HDD, 128GB SSD, GeForce GTX 1650 4GB (81LL004TGE)

Lenovo Ideapad L340-17IRH Gaming Black, Core i7-9750H, 16GB RAM, 1TB HDD, 128GB SSD, GeForce GTX 1650 4GB (81LL004UGE)

Lenovo Legion Y540-17IRH black, Core i7-9750H, 16GB RAM, 1TB SSD, GeForce GTX 1660 Ti (81Q4007BGE)

A dual channel is called a https://de.wikipedia.org/...nformatik) in the

https://de.wikipedia.org/...tertechnik, which allows two (or even more) https://de.wikipedia.org/...tsspeicher modules to operate in parallel on one https://de.wikipedia.org/.../Prozessor. For this, separate https://de.wikipedia.org/...i/Datenbus from the processor (CPU) or https://de.wikipedia.org/...controller are used for the individual modules. Simultaneous transmission over several busses allows more data to be transmitted per unit of time. https://de.wikipedia.org/...al_Channel

You can't connect 2 ram sticks at the same time. The more simultaneously the faster

Where does that really affect you?

All over. Faster ram = faster pc in itself. Browser closes opens faster. Games run with more fps. And something like that

It is not tragic if the RAM does not run in Dual Channel. Sure, Dual Channel is better, but it's not the end of the world if it's just single channel.