Laptops use smaller 2.5 inch hard drives for data storage due to limited physical space for the standard size 3.5 inch drives you would buy for a desktop PC. The 2.5 and 3.5 inch measurements refer to the size of the circular disk platters inside the housing.
The small physical size limits storage capacity because of smaller surface area per platter and fewer platters. Fortunately the capacities of these smaller profile drives come close to matching what is available on 3.5’s which is great for multimedia storage and games.
Higher RPM, or rotations per minute, really helps give that snappy feeling when opening applications or booting up your laptop. 2.5 inch are available in all the common speeds from 4200 RPM to 10,000 RPM. Manufacturers have to consider battery usage and noise so many laptops come with the drives using slower rotational speeds of 4200 RPM or 5400 RPM however.
An SSD or Solid State Drive is also a great option if you want pure speed. The pro’s of using an SSD for your laptop are low power consumption, silent operation due to no moving parts, and incredibly fast. The downside is cost per gigabyte is currently much higher than conventional disk drives.
Then there are Hybrid drives with a combination of SSD and mechanical parts. These aren’t as common but you get a good amount of the SSD speed but also the larger capacities and lower price of regular hard drives.
Upgrade Laptop Internal Drive or use External Hard Drive?
Upgrading the internal hard drive of your laptop is great for an overall speed boost when increasing RPM and platter density (more gigabytes in smaller area). Adding a second internal drive might also be an option for the bigger laptops out there, this way you get more speed, more space, and the same mobility.
If you just need more storage space then an external hard drive that links up through either USB, Firewire, or Thunderbolt ports. This option allows you to get much larger drives and even share the contents with your other laptops or desktops by just plugging into those machines.
External storage drives will almost always need an AC adapter rather than being powered from the Firewire or USB port directly, this may hinder mobility in some cases but these ports just don’t provide enough power. Some of the slower RPM or smaller capacity external hard drives can be powered directly from these ports but the price starts to go up because these are usually 2.5 inch laptop drives housed in an external enclosure.