[ntauthority]

The reserved memory would show up as 'dedicated' memory. Shared is just the amount of host memory that can be assigned to graphics resources, which usually equals the system memory or some amount derived from it.

If the full amount of system memory isn't showing on Windows that's likely an unrelated issue you're experiencing (for example with UEFI/BIOS memory mapping mismatching whatever else) and it working on Linux implies that either Linux gets fed different memory layouts or it parses this broken case fine unlike Windows.

If applications aren't using all the memory, and it's also not showing up as cached, that's odd as Windows usually tends to target around 80% of physical memory usage (unless you're really not using that many apps or there's another driver issue going on). Different OSes account for memory usage differently, and there's rarely one single 'memory used' indicator in modern operating systems.

[qwertox]

> If the full amount of system memory isn't showing on Windows that's likely an unrelated issue

Full amount of system memory is seen by Windows. It just refuses to hand out more than 16GB of RAM to it so I assume (maybe wrongly) that this is related to the other 16GB which the GPUs get assigned to but have no use for.

The memory graph in the task manager (Performance) never goes above 50%.