[sliken]

I think you are confusing channels and dimms.

The vast majority of any x86 laptop or desktops are 128 bits wide. Often 2x64 bit channels up till last year or so, now 4x32 bit DDR5 in the last year or so. There are some benefits to 4 channels over 2, but generally you are still limited by 128 bits unless you buy a Xeon, Epyc, or Threadripper (or Intel equiv) that are expensive, hot, and don't fit in SFFs or laptops.

So basically the PC world is crazy behind the 256, 512, and 1024 bit wide memory busses apple has offered since the M1 arrived.