What is the difference between an SSD and an HDD. These are two types of "hard drives" that you will often see and use. An SSD is a solid state drive which is flash storage. This means the storage is not on a physical disk, rather just "1's & 0's" in non physical memory. An HDD is a hard disk drive, this drive has a physical disk inside that spins and stores data on it. It can be at more risk of damage and future issues but it does tend to be much cheaper.