Why even your laptop should have 2 memory modules?

TL;DR: I was experiencing choppy MS Teams video calls and looking at Task Manager showed that it is the Intel _GPU_ that is saturated.

How to fix? Add a second same size memory module (SO-DIMM) to enable dual-channel memory operation for your integrated GPU, especially if you also have a 4k display (will help your CPU as well in a few applications).

Before:

 

After:

(look at the memory read speed almost doubling, but the latency also _decrease_ with double the RAM!)

I am lucky to have a Lenovo X1 Extreme Gen3.

1. One aspect that did not seem to be important to me before is that Lenovo equipped it with all the RAM in 1 SODIMM. Which means I started using it with a singe-channel memory configuration.
   
2. It has both the Intel GPU integrated (Comet Lake-H GT2, gen 9.5) with the CPU and a 4GB NVidia GTX 1650 Ti with Max-Q (power saving) Design (with reduced clock speeds, performance and of course power consumption) - but after reading up on it it only helps rendering but no display is directly connected to it - so whatever it prepares still needs to be copied over to the integrated graphics.
3. It has a 4K display, and I am used to using 4 virtual desktops actively interacting with each. meaning just rendering the screen at 60HZ will use 1.8GiB/s, and will have to keep 33+Mpixels (133MBytes) of screen estate up-to-date.
4. In addition to this modern browsers also use the graphics cards' 3D engines for rendering web pages and your daily video conferences also use the GPUs to encode your video and decode others' videos.

After reading up on this I realized the integrated GPU with 4k display is bottlenecked by the lack of dual-channel memory - so having two modules may be more important for speed than for the amount of memory.