A bit more complicated than that. The Intel firmware in the BIOS for pre Broadwell CPUs contained an assert which limited the ICs to 4GBit. You really badly can't put more than 16 DRAM ICs on a SO DIMM stick, they physically won't fit for example see https://en.wikipedia.org/wiki/SO-DIM...R3_SO-DIMM.jpg so that's the 8GB per stick limit you often see on Sandy Bridge, Ivy Bridge, Haswell machines. There's nothing really that would stop them working with 8GBit ICs / 16GB modules if someone updated the BIOS but Intel didn't let that happen. Except on Haswell-E motherboards because those are the latest in the "E" series as Broadwell-E doesn't yet exist so they work with 128GB RAM despite Intel Ark says 64GB max. http://ark.intel.com/products/82932/...up-to-3_60-GHz

This, by the way means that anything you read in Intel materials should be interpreted 'maximum memory supported using sticks available to us when we released this CPU'.

Now Samsung has 32 GBit DDR4 ICs http://gizmodo.com/this-is-samsungs-...hip-1744776220 and so theoretically it should be possible to manufacture 32GB (and very likely even 64GB) mobile sticks but I do not think anyone does. And whether there'd be support for them -- heaven knows what lurks in the BIOS this time.