Documentation here [URL] Can have up to 2X8=16G RAM. RAM speed is processor-dependent --  System will take one M.2 NVMe and one 2.5" SATA drive -- if ordered without the 2.5" drive, plan on needing to order the mounting hardware from Dell.  There should be no limits on capacity for either drive.  
I couldn’t find any reliable information on the upgradability of this laptop from Dell website or Google. Dell Inspiron 15.6 (Model: i3525-A617SLV-PUS). I hope someone could help me with a few questions below: Thank you in advance     Laptop main features: Processor & Memory: Drives: Operating System: Graphics & Video: Audio: Communications: Keyboard: Ports & Slots: Power Supply: Additional Information:
RAM & SSD upgrade options for Dell Inspiron 15.6 (Model: i3525-A617SLV-PUS) 
from Costco