A memory foam mattress combines a layer of memory foam with springs or support foam. What Is A Foam Mattress? Foam mattresses rely on air trapped within aerated substances (rather than springs) to offer support and bounce. Are you wondering what the difference between memory foam mattresses and spring mattresses is? Learn here with our comparison chart. What is a Memory Foam Mattress? A memory foam mattress contains multiple soft layers of polyurethane or polyol foam. Spring Mattress: Spring mattresses are firmer by nature than their foam counterparts.