I wonder why they added this limitation. Does somebody know if there another explanation other than Lenovo trying to maximize profit by forcing every customer who wants to go for 32GB of memory to get the most expensive CPU as well?
It appears that half of the memory is soldered to the board. That was also the case on my laptop mentioned above. It came with 4GB soldered, and 4GB in a slot. Why? I don't know. I was able to swap the 4GB with an 8GB and somehow it's still running in Dual Channel mode per CPU-Z so I guess it's no big deal, but I also find it odd.
Probably the model built around the lower-specced CPU has a "lesser" motherboard + power supply, that might draw less power on idle (so, better battery life) and be smaller/ligher, but would render the motherboard unable to output the spike currents required for the higher-specced CPU, nor the sustained current required for DRAM refresh of that much memory.
The model with the better CPU necessarily has a more power-hungry motherboard feeding it, and so can also feed current to 32GB of DRAM; but this likely comes at the expense of on-idle battery life.
