Eden Sheiko

Soldered RAM

The spec sheet of my 2019 laptop says 12GB of RAM is the maximum. A forum thread said otherwise, so I opened it up.

2 min read

My laptop’s spec sheet says I can’t have more than 12GB of RAM. I didn’t believe it.

Soldered RAM?#

I’m the proud owner of a Lenovo IdeaPad S540 15IWL GTX. I bought it sometime in 2019, as a future CS student who wanted the most laptop for the least money. It cost around 4,400 NIS, and for that price the specs were great:

  • CPU: Intel Core i5-8265U (4 cores / 8 threads, 1.6 GHz up to 3.9) or i7-8565U (4 cores / 8 threads, 1.8 GHz up to 4.6), depending on the config
  • GPU: integrated Intel UHD Graphics 620, plus a dedicated NVIDIA GeForce GTX 1650 Max-Q with 4GB GDDR5
  • RAM: DDR4-2400, 12GB maximum. 4GB is soldered to the board and there’s one SO-DIMM slot, so you add (or swap) a single stick

Great machine. And back then I thought, 12GB, that’s fine.

It’s not fine. Of course it’s not fine. Sam Altman, I’m looking at you.

The datasheet says no#

Almost every spec sheet I could find agrees on the same number: 12GB max. Here’s Lenovo’s own one:

ideapad_S540_15IWL_GTX_Spec.pdf

So the plan was simple: live with 12GB.

Then I read on some forum that you can go higher than the datasheet says. That was it, I was going for it.

Getting to the stick#

The 4GB that’s soldered on the board is stuck there, nothing to do about that. But the slot is a normal SO-DIMM slot, and that’s the only part that matters.

Getting to it is easy. Remove the bottom cover and you’ll see a silver sheet with gold tape sitting over the RAM. Peel it back carefully and the stick is right there. In my case it’s an 8GB stick, labeled PC4-2666V, which the CPU runs at 2400 anyway.

The result#

I put in a 16GB stick instead of the 8GB one. 4GB soldered + 16GB in the slot = 20GB, eight more than the datasheet claims is possible.

My guess (and it’s only a guess) is that the 12GB number is just what Lenovo tested and shipped back in 2019, not a real hardware limit. The memory controller in the CPU can handle a lot more than that, and the soldered 4GB doesn’t get in the way of a bigger stick.

Maybe next I’ll try a 32GB stick. If I do, I’ll write about it here.