How AI chips work
Brain chips and memory chips
Every AI chip has two jobs: think and remember. Two different kinds of chip do them, from different companies. In 15 minutes, you learn who does what, and why your MacBook is built the way it is.
- Logic chip
- A chip that thinks. It does the sums and makes the decisions. Also called a processor.
- Memory chip
- A chip that remembers. It holds the data the logic chip is using right now.
- DRAM
- The most common memory chip. It is the "RAM" in a laptop.
- Unified memory
- One shared pool of memory that every part of the chip can use.
01 · The question
The laptop at the coffee shop
A friend buys a new MacBook. The shop worker says: "It has unified memory. That is why it is fast." Your friend nods, then whispers: "What does that mean?"
You do not know yet. Picture a chef in a small kitchen. The chef does the cooking. The fridge holds the food. A good kitchen needs both, and they must work together.
A chip works the same way. After this lesson, you can answer your friend.
First, a quick guess.
02 · Your guess
In a MacBook, how do the CPU and the GPU use memory?
The CPU is the main brain. The GPU is the picture brain. A wrong guess costs nothing. Guessing first helps you remember the answer. Pick one to open the next part of the lesson.
03 · The machine
The chef and the fridge, step by step
Press Next step to see each step. Steps 1 to 3 meet the two kinds of chip. Steps 4 and 5 show how they work together. Step 6 shows both in real devices.
04 · Remember
The chip thinks. The memory remembers. Both must keep up.
A logic chip is only as fast as the memory that feeds it. Today, AI makes memory chips scarce, so memory makers are in the news as much as chip designers.
Fridge next to the chef
The chef reaches out and the milk is there. The chef cooks all night. This is memory close to the logic chip.
Fridge in the next building
Every egg needs a walk. The chef stands and waits. This is memory far from the logic chip.
Logic or memory? Three quick rules
- It decides and calculates. That is a logic chip. Examples: an Nvidia GPU, an Apple M-series chip, an AMD processor.
- It holds data right now. That is a memory chip. Examples: DRAM in a laptop, HBM in an AI card.
- One device needs both. Nvidia and Apple design the logic. TSMC builds it. Samsung, SK hynix and Micron make the memory.
Why does Apple share one pool?
Many older laptops gave the CPU one memory and the GPU another. To share a photo, the laptop had to copy it from one to the other. Apple's chips use one pool, so every part reads the same data with no copy. Apple says this raises speed and saves power.
05 · Two checks
Pass two checks to finish
A miss is fine. Each miss gives you a new case.
Check 1 of 2 · Logic, memory or shared?
Check 2 of 2 · Fill in the sentences
Tap the right word for each blank. If you tap the wrong one, you get a hint.
06 · Tell a friend
Your one-minute answer
Say it in your own words. Here is a version you can use:
The one-minute version
"A chip has two jobs. A logic chip thinks, like a chef. A memory chip remembers, like a fridge. Nvidia and Apple design the logic chips, and TSMC builds them. Samsung, SK hynix and Micron make most of the world's memory chips. A fast chef with a far fridge waits, so memory must be close. In a MacBook, Apple puts the CPU and GPU on one shared pool of memory. That is unified memory. They read the same data without copying it."
| Logic chip | Thinks. Nvidia GPU, Apple M-series chip. |
| Memory chip | Remembers. DRAM, and HBM in AI cards. |
| TSMC | Taiwan. Builds logic chips for Nvidia and Apple. |
| Samsung, SK hynix, Micron | Korea, Korea, USA. Make memory chips. |
| Unified memory | One shared pool in Apple chips. No copying. |
Try it today. Open "About This Mac" on a Mac, or the spec page of any laptop. Find the memory line. Then ask an AI: "explain unified memory like I am 12". Check its numbers.
This lesson explains how the industry works. It is not advice to buy or sell any stock.
Back to all lessons