I bought a Dell 3910 last December.  Came with 8GB of ram made by Samsung.  I purchased another 8GB stick made by Crucial (CT8G4DFRA32A) from Newegg at the same time.  Same 1.2v, CL22, 3200MHz speed as the factory installed ram.  Installed the added ram the day the Dell came in. No problems whatsoever.  Got the Crucial for less than 40 bucks.
I found the specs for the desktop memory (1.2V DDR4 3200 dual rank).  Anyone have success with the various options out there (other than buying from Dell)?
Inspiron 3910 Memory Upgrade Options