Their compatibility site is always a good spot to find out what ram/storage upgrade options a laptop has
since finding an official manual that is actually useful in that regard can be a pain
some laptops are know to run with configurations that aren't listed either in the official manual nor on these compatibility lists
but that stuff is usually a bit of a gamble whether it will work in your specific configuration
e.g. 4GB DDR2 S0DIMM and 16GB DDR3 S0DIMM ram sticks
both came out at the very end of the life cycle of that ram generation and are pretty rare
and basically no laptop from that era officially supports them
i'd love to see if my thinkpad will boot with 16GB sticks but i don't have any atm and they are really expensive :Sadge:
if it works i could get that laptop up to 32GB of ram
and with a motherboard swap even 64GB.