| Base Of Difference | Hard disk | Optical Disc |
| Spin faster | Hard disk drives spin mush faster then the Optical disc. | Optcial disc drives spin much slower then the hard disk. |
| Energy Saver | As Hard disk filled with helium which can decrease the energy need for spining them thus it is faster | Optical is slower |
| Sprial Tracks | Hard disk store data in spiral tracks so it is musch faster | As not all store data in spiral tracks so these are slows. |
| Storage capacity | We can store more data on hard disk on a similar sized optical disc so higher data density. | Due to lower data density it is very slow then hard disk |
| Distance | Hard disk need less distance to cover for head as have the higher data density
| Optcial discs head need to travel so much distance due to low data density |