The biggest problem with these chips was the limited amount of memory you could get on the motherboard. Older motherboards were limited to 512K or 640K. In the early years this was a tremendous amount of memory. But as software RAM requirements increased, you needed more RAM.
A memory expansion card was the answer to increase memory on older motherboards. These cards allowed you to add additional RAM chips to the card, and plug the card into your motherboard. However, accessing RAM on the memory expansion card was a little slower than accessing RAM directly plugged into the motherboard.