Whether you're shopping for a new computer or looking to upgrade one, you'll be faced with the question of computer memory. What's the advantage of more RAM (Random Access Memory)? What does a cache on a hard drive do? Why is a larger cache better?

RAM Basics

RAM comes in "sticks" that you install on the motherboard. Your computer uses it to rapidly store and retrieve commonly needed data. The more of it you have, the less your computer has to access the much slower hard drive or virtual memory.

System Performance

If your system does not have enough RAM for the things you want to do, it will start up slower, and programs can take longer to load and can perform sluggishly. You can actually run out of RAM, at which point additional programs cannot load.

Virtual Machines

If you have enough RAM, you can run one operating system inside of another, using programs like VMWare or Virtual PC. This way, you can test-drive new operating systems without fully installing them, or try experimental behaviors that could otherwise cause harm to your data.

Cache Memory

Hard drives and CPUs (Central Processing Units) use caches located on the device itself. These caches operate like RAM but are even more efficient. The larger the cache, the more data it can keep close by for rapid processing, which makes for overall faster performance.

Adding RAM

If you want to put more memory sticks in your computer, refer to your motherboard's documentation to see what types of sticks are compatible, and visually inspect your motherboard to see how many memory slots are available.

Source:

Defining RAM

System Memory Overview