Ah yes, that has a single RAM slot. Crucial only shows an 8GB module for it:

https://www.crucial.com/compatible-upgrade-for/lenovo/thinkp...

So I don't know, that may well be the limit. OTOH, if there a larger compatible module from another manufacturer, it wouldn't surprise me if it just worked. Lenovo generally doesn't put arbitrary restrictions on RAM size.

Processors have RAM limit as well, independent of vendor. https://ark.intel.com/content/www/us/en/ark/products/75992/i...

Look at "Memory specification" part.

Can you call it a limitation of the processor? I thought it was with the accompanying chipset - https://www.easytechjunkie.com/what-is-the-difference-betwee... .

Sure, the only real limitation inside the processor is the number of addressing bits if I remember correctly. However, in case of laptops I think it doesn't matter since they're kind of sold as a platform. The main point was - it might not be possible to extend RAM.

Thanks for the link. Indeed, that page lists a 16GB limit, so if that is the processor in OP's machine there may be hope. I do have 16GB (8GBx2) in my older X220 Tablet.

For the X250, I can confirm that it handles the 16GB. Investigated it once, haven't bothered actually upgrading, though.