laptop ram

Hi, I have a Razer Blade 15 (2018). This laptop comes standard with 16Gb DDR4 SODIMM 2667Mhz RAM (2x 8Gb). As it can be extended to 64Gb I’d like to do this within the next few weeks. My question is, I’d like to go for RAM that is 3200Mhz rather than 2667Mhz for obvious reasons, how do I know...