11-27-2017 07:50 AM
Welcome to the Community Forums.
As per product specifications:
8GB max / 2133MHz DDR4, one DDR4 SO-DIMM socket
So you have a single module to replace the current 4GB to a compatible 8GB DDR4 RAM.
Here is the hardware manual for the disassembly describing the steps to perform the RAM replacement.
FRU list page 74 item 11 for the OEM tested ram.
I hope this helps answer your query.