Memory vs. Storage

This is basically semantics; a geek's gripe, if you will.

It often happens when people talk about "filling up their hard-drive", and they mistakenly say:"I ran out of memory!"
Err... no you didn't! You ran out of "storage"!

Let's talk for a minute about the difference between the two: First, when you buy a new PC, there will generally be two separate numbers followed by "GigaByte" - for example, 500GB and 4GB.

Storage

The larger number in the above example, 500GB, is your "storage" - This is the capacity of your hard-disk. When you fill your computer with movies, music, photos and other files, they are all stored on the hard-disk. When the hard-disk becomes very close to being full, it can seriously affect the performance of your machine. This is a common issue with many older notebook PCs with small disk capacities (under 300GB) - A common fix for this is to "delete the old files you don't need (or transfer them to an external hard-drive), and defragment your hard-disk".

When your "Storage" is full, your hard-disk will change from blue to red

Memory

The smaller number in the above example, 4GB, is your "Memory" - or more exactly, Random Access Memory (RAM), sometimes also called, "System Memory". Nothing is stored in the RAM, nothing long-term, anyway. The RAM's job is to help the processor (CPU) do its computations as fast as possible.

Analogy one: Imagine that your PC is a car. You have the gas-tank, that's your "Storage", or hard-drive. Then you have the engine, that's your CPU (Central Processing Unit), or processor. Well, your RAM is like the carburetor; it's what helps the engine (CPU) run as efficiently as possible. You might have a big V8-engine, but if the carburetor is too small, the engine won't be able to mix enough air with the fuel and it won't produce much power. When your CPU is making computations, ie. "computing", it needs to store and retrieve thousands of tiny pieces of data relevant to those calculations, as quickly as possible, while it's crunching the numbers - your hard-disk is way too slow for this process. This is what the RAM is for. If there is not enough space in the RAM to store all the pieces of data for each computation, it will take that much longer for the CPU to finish the process. This is particularly important when you are trying to work with many large files, such as rendering many Gigabytes worth of video, for example.

Analogy two: Imagine you had to collate multiple copies of a 20-page document - In this case, you are the CPU - you are doing the work. In order to collate these documents efficiently, you would need enough space to make 20 separate piles of each page. You would need the "desk-space" to do the work. Now imagine if your desk was only large enough to hold 10 piles of each page (no putting the rest on the ground!), you would only be able to do 10 pages at a time, and then you'd have to put the first lot aside, swap them with the unfinished ones, and do the second lot of 10 pages, and finally bring them together to make the 20-page documents - what a hassle. In short, if you didn't have enough desk-space, you would have to double-handle everything, and the entire process would take much longer and cause more stress than necessary. In this case, RAM (Memory) is like your desk-space. If you don't have enough, it can slow down the computations of the entire system - Even if you have a high-powered processor like a Core-i7.

The Vista days...

This was quite a common problem not so long (4-6 years) ago. When Windows Vista came out, it was recommended to have at least 2GB of RAM, just so Windows itself could operate smoothly, let alone other programs running on top of it. At the time, memory was prohibitively expensive, and the first place PC manufacturers looked to cut costs was with RAM. Many systems shipped with only 1GB of RAM. The original Vista (before Service Pack 1) was already a bit sluggish, but coupled with a lack of RAM, it made for a very labored experience.

So, how much RAM should you get?

Thankfully, RAM prices have dropped almost ten-fold since then, and many a system has been rejuvenated with a quick 4GB memory install.

Now that the price of RAM is so reasonable, 4GB is thought of as the "minimum", and 8GB the solid "recommendation" for the average user. For professionals in the video editing industry, 16GB is sometimes not enough, so 32GB or even 64GB is often suggested.

A system with a moderate to heavy workload can easily use over 5GB of RAM