SO-DIMM format DDR4 memory modules with a capacity of 32 gigabytes are starting to appear on the free market. For example, the German price aggregator Geizhals.de provides links to stores where the Samsung RAM bar (M471A4G43MB1-CTD) can be purchased at prices ranging from 360 to 440 euros. The nominal frequency of the module is 2666 MHz, the supply voltage is 1.2 V, the delays are CL19.
Even if you take into account the novelty of the product, the amount of 400 euros looks too high. For example, the 32-gigabyte DIMM DDR4-2666 desktop slats from Samsung are priced at around € 270. At such prices, compact RAM modules will be used only in a few workstations, where the memory capacity is critical for professionals. In the meantime, gamers will continue to be content with smaller modules.
As for compatibility, 32-gigabyte SO-DIMM DDR4 is supported by at least modern notebooks based on Intel Coffee Lake processors. One of the users of the site NotebookReview reported on the successful upgrade of its MSI P65 Creator.