Comment 6 for bug 1752440

lshw shows two banks of memory but MAAS is still correctly calculating the output from lshw. There are twelve occurrences of the line <size units="bytes">34358689792</size> which is 384GB. I looked up the part number reported by lshw, 72ASS8G72LZ-2G3B2. According to [1] each DIM should be 64G, not 32G. There is a commit upstream [2] which adds support for DDR4 RAM and another [3] which adds support for larger amounts of RAM found in DDR4 RAM. As [1] says this module is DDR4 I suspect the version of lshw in Ubuntu needs both these patches.

@dgrosvenor could you try building lshw in rescue mode to confirm?

sudo apt install git gcc make
git clone https://github.com/lyonel/lshw.git
make
sudo ./lshw -xml > lshw.log

[1] https://www.micron.com/parts/modules/ddr4-sdram/mta72ass8g72lz-2g3
[2] https://github.com/lyonel/lshw/commit/0ea2e95b3ccdeb3834bec6fe22d0794a65e8c37a
[3] https://github.com/lyonel/lshw/commit/ab43c697ebaff3e5138c43a39a17f69859cde87d