What is RAM, and how much do you need?
RAM, or random-access memory, is your computer’s working space: whatever you have open right now, loaded where the processor can reach it fast. It’s small and very fast, and it forgets everything when the power goes off, which is why you save files to the drive. When RAM fills up, the computer slows to a crawl.
The desk and the filing cabinet
Think of RAM as your desk and the drive as a filing cabinet. The desk is small but everything on it is right there. The cabinet holds everything you own, but getting something out takes a trip. Opening an app means carrying it from the cabinet to the desk.
That’s why “memory” and “storage” are different numbers on a spec sheet. A laptop might have 8 GB of RAM and a 256 GB drive. Phone ads that say “256 GB of memory” almost always mean storage.
Why it forgets
RAM holds each bit as a tiny electric charge in a microscopic capacitor, and those charges leak. The memory refreshes every bit many times a second to keep it. Cut the power and the refreshing stops, so everything is gone. Unsaved work lives only in RAM, which is why a power cut loses it.
What happens when it fills up
The computer doesn’t crash. It starts borrowing space on the drive and shuffling things back and forth, called swapping. On an SSD that’s noticeable. On an old spinning hard drive it’s miserable, because the drive is thousands of times slower than RAM. Memory near 100% and the disk pinned at the same time is the classic sign.
Most slow computers aren’t short on processor speed. They’re waiting on something slower: memory that’s full, a hard drive with a spinning plate, or the internet. The processor is so fast that every trip to anything else is a long wait by comparison. Here’s how long, if one processor tick took one second.
This is the same toy that’s in the app.
If one processor tick took one second, and everything else stretched to match.
How much RAM you need
About 8 GB
Email, homework, video calls and a reasonable number of browser tabs.
About 16 GB
Modern games, lots of tabs and heavier multitasking.
32 GB or more
Big creative work like editing long 4K videos.
More than you use does nothing. Watch your memory on a normal day: if it never goes past about 60%, more RAM won’t change anything you can feel. And check whether your laptop can take more, because on many thin laptops it’s soldered to the board.
Questions people ask
Is memory the same as storage?
No. Memory, or RAM, is the fast working space for what’s open right now, and it forgets without power. Storage is the drive, where everything is kept for good. Storage is usually more than a hundred times bigger.
Will more RAM make my computer faster?
Only if you were running out. If memory is often near full, more RAM stops the swapping and things speed up a lot. If you already have plenty, extra RAM sits empty.
Learn it by taking one apart
The app teaches RAM in Module 8, The Desk and the Filing Cabinet, and Module 9, How RAM Remembers, where the crew finds Grandma Ruth’s laptop at 91% memory and fixes it.
How Computers Work is a course in five-minute lessons, with something to play with in every one and an old laptop the crew fixes along the way. Part I is free. Coming soon to iPhone, iPad and Android; the toys on the course page work right now.
Keep going
SSD vs. HDD: which is better?
Flash chips vs. a spinning plate, and why the swap makes old computers fast.
CPU vs. GPU: what’s the difference?
A few brilliant cores vs. thousands of simple ones, and why AI wanted the second.
Router vs. modem: what’s the difference?
One box connects the house, the other shares it. Which to restart first.