Because they install two 4GB sticks of ram to reach a total of 8GB. It's important to make this distinction because 2x4GB is faster than 1x8GB, but it doesn't a

Because they install two 4GB sticks of ram to reach a total of 8GB. It's important to make this distinction because 2x4GB is faster than 1x8GB, but it doesn't allow for a trivial upgrade by just sticking in another stick as you'll probably need to replace both instead.