TFLite vs ONNX Runtime: Pi Zero Latency at 32ms vs 89ms

#edgeai #raspberrypi #tflite #onnxruntime

ONNX Runtime is 2.8x faster than TFLite on Raspberry Pi Zero — and I didn't expect that.

Most edge AI tutorials assume you're deploying to a Pi 4 or Jetson Nano. But what if you're stuck with a Pi Zero W (single-core ARMv6, 512MB RAM) because your budget is $10 per unit and you need to ship 500 devices?

I ran the same MobileNetV2 model through both runtimes on a Pi Zero W to see which one actually delivers. The results flipped my assumptions: ONNX Runtime averaged 32ms per inference while TFLite took 89ms. That's not a rounding error — it's the difference between real-time and slideshow.

Here's the full benchmark setup, the gotchas I hit, and when TFLite might still be the right call.

Detailed view of a circuit board and electronic components on a table. — Photo by Tanha Tamanna Syed on Pexels

The Hardware Constraint That Changes Everything

Raspberry Pi Zero W specs:

1GHz single-core ARMv6 (BCM2835)
512MB RAM
No NEON SIMD extensions
Cost: $10

That last point matters. If you're building 500 units, the difference between a $10 Pi Zero and a $55 Pi 4 is $22,500. You can't just throw hardware at the problem.

Continue reading the full article on TildAlice