Tesla's FSD chips: Integer vs. Floating-point
At Tesla's shareholder meeting Elon said that, "integer operations are fundamentally more efficient than floating-point operations...integer is much more power efficient, much more silicon efficient, but you actually have to train for integer inference - everyone else is training for floating-point - that's a niche technical detail, but it's actually very important."
So what does he mean?
Well, imagine you’re driving a Tesla, and the car’s “brain” has to think really fast to decide what to do every second:
- Is that a shadow or a pothole?
- How far away is that car?
- Can I make this turn safely?
All of that happens millions of times per second - like a giant video game running in real life.
Two Ways the Car’s Brain Can Do Math
Computers think using numbers, and there are two main kinds of math they can use:
Floating Point (“fancy math”) – handles decimals like 3.14159 → Super accurate, but slower and more energy-hungry.
Integer (“simple math”) – handles whole numbers like 3 or 4 → Slightly less precise, but way faster and more efficient.
Why Tesla Likes Integer Math
Tesla’s Full Self-Driving (FSD) chip in the car runs AI models that turn camera video into driving decisions. To make this happen in real time, Tesla needs speed and efficiency more than perfect decimals.
Here’s the trick:
The AI doesn’t need to know if something is 3.14159 meters away. It just needs to know it’s about 3 meters away - that’s good enough to brake safely.
So instead of wasting power on floating-point math, it uses integer math, which is like rounding to the nearest whole number.
That’s enough precision for driving, and it makes everything run faster.
What Happens Inside the Chip
Think of the chip like a big army of tiny workers (transistors).
Integer math: the workers do simple, quick jobs - they don’t get tired and don’t need much energy.
Floating point math: the workers do harder, more detailed jobs - they need more space, more time, and more power.
Tesla’s chip uses millions of small, efficient workers (integer units) that can handle tons of simple math at once - kind of like having a million fast-thinking ants instead of a few slow geniuses.
The Result
Because Tesla uses integer math:
- The car reacts faster (less delay between seeing and acting).
- The computer uses less energy, so there’s more battery power for driving.
- The chip costs less to make and runs cooler.
- Tesla can process huge amounts of video data cheaply in its training supercomputer.