That's actually pretty impressive, that they have a AM4 platform in such a tiny chassis. At first I was going to poo-poo the use of an A320 chipset, but after more thought I realized it doesn't matter. There's no PCIe slot, there's no reason to overclock this platform, and A320 sips power compared to A520. The only problem is Zen3 APUs likely won't be compatible.

Ryzen 2000 and 3000 models of the G and GE lines, with a maximum TDP of 65W are supported. Also a select few of the Athlon line.

Well, the Asrock X300 seems a better alternative. And cheaper.

Since it has COM ports it appears to be custom thus i would not be surprised if it will support Ryzen 5000 APU's in the future ROM size 16MB will be enough for Ryzen APU's only

Fox2232:

On HW side per $, yes. But it is at least twice as big.

There is always a trade off when it comes to hardware. But comparing to traditional desktop computer the Asrock X300/A300 is a breath of fresh air. I am biased because I am decided to buy one and I like it. Nevertheless, the small computers trend will continue to improve.