Hi, there! 

I have a quick question about RAM upgrade on my S340. Serial number is ********. It has 4GB on-board memory + 4GB stick. I want to replace the stick with 16GB one. Is there a chance to make it work and detect all the memory installed? If yes - what kind of memory would be compatible?

Thank you!

Edit notes: Removed SN for member's protection 

MTM : 81NC00C3BM S340-15API Laptop (ideapad) 

Hi nejelaq,

Welcome to the Community Forums.

Technically as per product specifications:

12GB max offering / 2400MHz DDR4,
optional 4GB memory soldered to systemboard, one DDR4 SO-DIMM socket

There are however some sellers that markets the same variants like 81NC00GGMJ for a 20GB total with 16GB DDR4 on the single available slot although manufacturer's max offered is 12 GB with 8GB on the free slot. There maybe a chance for 16GB 2400MHz DDR4 but we cannot guarantee it working as those certified offered ram do.

Checking with parts lookup (click compatible tab> Commodity list> Memory) only offers 8GB to replace your current 4GB (16GB not offered via Lenovo).

PN 01AG864 SODIMM,8GB,DDR4,2666,HYNIX

PN 01AG855 M471A1K43DB1-CTD

PN 01AG843 8GB DDR4 2666 SoDIMM,Ramaxel

I hope this helps answer your query.

Regards