I have a MacBook Pro 2018. Currently it has two 4GB LPDDR3 2133MHz memory cards. My son has just bought a new computer and already upgraded the memory and has given me his Samsung 8GB 1Rx8 PCA-2666V-SA1-11 card which I think is DDR4. If I take one of the 4GB LPDDR3 cards out of my Laptop can I replace it with the new Samsung DDR4 card? First would it fit and second if it did would I gain anything?