The ToyBrick RK3399 Pro is a developer board that is powered by an RK399Pro SoC, which integrates an ARM Mali-T860MP4 GPU and an RK1808 NPU that can achieve up to 3.0 TOPS. The board can dual-boot Android and Linux out of the box and comes with up to 6 GB RAM and 32 GB of eMMC flash storage.
https://www.notebookcheck.net/The-ToyBrick-RK3399-Pro-a-Raspberry-Pi-sized-SBC-that-outperforms-the-NVIDIA-Jetson-Nano.420750.0.html
You don't buy a jetson for the cpu cores or just the basic features of the gpu.
Well at $300 why not get a NVIDIA Jetson TX1 and compare specs to that price :)
for that price, only people who never check buys. i rather buy intel micro pc.