How I solved the problem: I ordered new 32GB Ram from Crucial and it worked.
Hello, I have a Dell XPS 15 7590. The Laptop has two RAM Slots. 2x 4 GB RAM were installed. I wanted to upgrade it with 2x 16GB RAM. However when I replaced both Slots with the new RAM. When I started my Laptop I didn't get an image. Only the status bar began blinking white and amber lights. Always 3x White and then 2x Amber and then repeating the cycle. I reinstalled both old RAM sticks (2x 4GB) and the Laptop booted just fine. I only got one message from some Diagnostic tools before booting into Windows which said that the previous boot attempt didn't have memory or something like that.  After that I tried to install only one new RAM Stick. I installed it in the right slot (see the picture).  This worked fine and I could boot as always. I also tried to install the other RAM Stick in the right slot. This worked fine too. Meaning that the  new RAM Sticks probably aren't problem. However when I tried to install one of the new RAM Sticks in the left slot and install one of the old RAM Sticks in the right slot. It didn't work. This leads me to believe that there's some problem with the left slot, which prevents me from upgrading it. It would be great if somebody could help me to solve this problem. If more information or pictures are needed, please ask. I will send them to you.[IMAGE]
Can't upgrade one RAM Slot