Is it possible to use old RAM on new MacBook? My current MacBook Pro, a early-2013 13" i5, is getting very slow and I therefore want to buy a new one. However, I want to wait until the next generation comes out. In the meantime I will change the RAM from 4GB to 16GB.

My questions is if the RAM for the early 2013 macbook will work in the new MacBook Pro?
I'll make it quick for you : MacBook Pro and MacBook Air have the ram now soldered to the main board. 

You won't be able to upgrade the ram on the new MacBooks.