Need to know which is better and faster for laptop memory upgrade

Question

What is the difference and which is better for a laptop memory upgrade:  SDRAM, DDR SDRAM, SIMM?  One site suggested DDR SDRAM and BB suggested SO DIMM

Answer 1

SODIMM is the physical form factor of the module, DDR SDRAM is the actual memory type.
SIMMs are an ANCIENT form of memory module.  If you have a system that uses SIMMS, you will spend less money throwing your computer in the trash and buying a new one.
Non-DDR SDRAM is also ancient.
Each system can only use one type of memory, i.e. you can't use DDR memory in a system that only used non-DDR memory, and you can't use DDR2 memory in a DDR system.
To find out if the configuration is 2x256 or 1x512, you'll need to look at what is installed.
*disclaimer* I am not now, nor have I ever been, an employee of Best Buy, Geek Squad, nor of any of their affiliate, parent, or subsidiary companies.