You can either go to the Dell support page, type in your service tag number, and in documentation the specs for your system can be displayed stating memory specs. Or go to Crucial and type in your model number and the specs for compatible memory will be displayed. Crucial also has a small app that you can install which will tell you how many SODIMM slots you have and what RAM is populated in those slots. [URL]
Is this "Crucial CT16G4SFRA32A memory module 16 GB 1 x 16 GB DDR4 3200 MHz" compatible with my laptop?
dell inspiron 15 3000 series ram compatibility