RE: 32GB in Inspiron 13 5000 series (5378)???
For this I would suggest you NOT to update the BIOS to 1.4.0 (or any version at all, I am not sure what is the version it starts to have issues.).
I can't say for sure it will affect you, but my 5378 just could no longer boot with my pair of 16GB RAM both installed. I need to detach either one of them. Then the other one can stay in either slot and the computer boots normally.
It was working flawlessly for two weeks until a few days ago which I only upgraded the BIOS, so I have to say that's the cause for me. Just for your reference.