AI PCs Aren't Good at AI: The CPU Beats the NPU

I think the results show that just in general the compute is not used well. That the CPU took 8.4ms and GPU took 3.2ms shows a very small gap. I'd expect more like 10x - 20x difference here. I'd assume that the onnxruntime might be the issue. I think some hardware vendors just release the compute units without shipping proper support yet. Let's see how fast that will change.

Also, people often mistake the reason for an NPU is "speed". That's not correct. The whole point of the NPU is rather to focus on low power consumption. To focus on speed you'd need to get rid of the memory bottleneck. Then you end up designing your own ASIC with it's own memory. The NPUs we see in most devices are part of the SoC around the CPU to offload AI computations. It would be interesting to run this benchmark in a infinite loop for the three devices (CPU, NPU, GPU) and measure power consumption. I'd expect the NPU to be lowest and also best in terms of "ops/watt"

> Also, people often mistake the reason for an NPU is "speed". That's not correct. The whole point of the NPU is rather to focus on low power consumption.

I have a sneaking suspicion that the real real reason for an NPU is marketing. "Oh look, NVDA is worth $3.3T - let's make sure we stick some AI stuff in our products too."

I assume you're both right. I'm sure NPUs exist to fill a very real niche, but I'm also sure they're being shoehorned in everywhere regardless of product fit because "AI big right now."

The shoehorning only works if there is buyer demand.

As a company, if customers are willing to pay a premium for a NPU, or if they are unwilling to buy a product without one, it is not your place to say “hey we don’t really believe in the AI hype so we’re going to sell products people don’t want to prove a point”