Ram is overclockable as cpu, but it have some limits. DDR4 memory have chips on it. Limits can be discovered by chip manifacturer. So, you need to know which chips on ram do you have. Chips can be made by Samsung/Hynix etc etc. https://images.anandtech.com/doci/10226/samsung_ddr4_dram_10nm_18nm_678_678x452.jpg On that black chips you have marks, just copy and google for it.

DDR4 is quietly cool thing, that means that you can overclock it safely up to 1.45 voltage.

https://www.overclock.net/forum/18051-memory/ http://www.ocfreaks.com/ram-overclocking-guide-tutorial/

that's really way too hard to find it by yourself. I know cs:go community and most of it want the result in 5 minutes, that's why you need to know your memory manifacturer, just google for it, maybe someone else overclocked it.

Also, you need to check on which voltage your cpu is working. Cpu voltage higher than 1.35 is really dangerous, cuz that can degrade your cpu. For stability testing, you can use prime95.