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Comment by Robotbeat | Hacker News Reader

From what I understand, Pegasus consumes about 500Watts, compared to under 100 Watts for Tesla's FSD computer. Elon in particular emphasized the performance per watt (as it's always possible to cram more chips to increase performance if you ignore cost and power consumption).

The comparison made in the video: 500Watts for an hour consumes about 2-3 miles of range. In a city in slow traffic, going 12mph, that's a significant range reduction. So you might have a 10% improvement in range for the Tesla ASIC in low speed conditions.

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Its incomparable though. The Pegasus has far more compute power.

Just because the Pegasus has 500W worst-case TDP doesn't mean that its average case would be 500W constant. If you scale back your code and idle parts of the GPU, you can drop the energy cost arbitrarily.

At least, that's how GPUs on desktops work. They only use a ton of power if you give them a ton of work. Write your code in an energy-efficient manner, and the 2080 Ti will drop down to 20W, or scale all the way up to 300W.

https://www.tomshardware.com/reviews/nvidia-geforce-rtx-2080...

Modern chips idle very well. With the right code, the Pegasus could be tuned to only use 100W (assuming good enough programmers). But Tesla's chip will NEVER be able to scale above 100W.

Pegasus's chip is more general purpose and doubtless has far more general purpose compute power. But that's irrelevant. What's relevant is Tesla's chip is optimized specifically for their NN pipeline whereas Pegasus is based off of general purpose GPU architecture, thus Tesla's chip achieves a better TOPS per Watt than Pegasus. And it'd be strange if it didn't.

"Tesla's chip will NEVER be able to scale above 100W" okay, based on what? Tesla has a higher performance chip in the pipeline right now, and they could've used more silicon to achieve more TOPS if they needed it.

EDIT: Pegasus has 500W at 320 TOPS. Tesla's has 72 Watts at 144TOPS. Thus Tesla's chip, because it's focuses specifically on Tesla's NN pipeline, is about to get almost 4 times to performance per watt of the Pegasus and is much cheaper. Tesla's NN chip wouldn't help your video game, and Tesla isn't intending to compete in all the markets Nvidia operates in.

> Pegasus has 500W at 320 TOPS. Tesla's has 72 Watts at 144TOPS.

Theoretical TOPS which can only ever execute within the 32MB SRAM that Tesla has created. Otherwise, Tesla's compute chip is stuck at 68 GBps LPDDR4 RAM. Pretty slow.

Pegasus uses HBM2 chips at 500GBps. Pegasus will be able to efficiently compute neural networks that are larger than 32MB in size.

Tesla is making big bets about this tiny 32MB SRAM. Bits and pieces of the CNN can fit in there, but almost certainly not the entire neural network.

You're right that this is a specialized chip. But even for NN / Deep Learning inference, it seems a bit underpowered to me from a RAM perspective

Specmanship doesn't matter. What matters is how fast it's able to execute on the task at hand and for what cost in terms of purchase price and energy.

Nvidia's offering can be really good, and so can Tesla's.

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