This message was posted on behalf of Intel Corporation
Only one module is supported per system. A second may be installed, but will only serve as a small storage device (using Intel® Optane™ Memory as an SSD is possible but unsupported).
It may not sound like much, but thanks to the way that our caching algorithm works, one 16 GB module is usually plenty for most users. The 32 GB sticks are actually intended for "power users who often use a variety of data-intensive applications such as prosumers and gamers."
We hope this helps. If you have any additional questions or concerns, feel free to let us know.