I was looking at the O-Pi Zero's I have and am scratching my head on it because they were advertised as H3 Quad Core CPUs. They are not, but they use an H2+ CPU which is also a Quad Core. In looking at the differences between the two CPUs, I could find very little documentation for it.
 
But there is Good Old Wikipedia. There was no information on the H2+ but there is information on the H2 (as used in the O-Pi 2G-IoT). In comparing it to the H3 under it, the only difference between the two is the L2 Cache - the H3 has it, the H2 does not. Question is, dos the H2+ has a minimal cache? Don't know but from the looks of it, it might has a smaller cache than the H3. This would make some sense.
https://en.wikipedia.org/wiki/Allwinner_Technology#H-Series
 
So the O-Pi 0 has a lot more going for it than it seems. But the price difference makes one head scratch. If the H2 and the H3 CPUs re so much alike, why make a separate board using the H3? And on the H3 & H5 O-Pi Zeros the Ethernet and USB is removed to put in a Camera Port and a HDMI port; though you can get 2 USB Ports by adding the O-Pi Zero Expansion board with it. It will set you back $10 more than the H2 version. They are trying to hit different markets here all at once with the same tiny board.
 
This is interesting, as using the H2/H2+ drives the price down to what one can get a less than $10 board in the O-Pi 0 Series.  It also means that its cousin the O-Pi Zero Plus 2 runs on the H3 and H5 CPU, which is strange for it gives the O-Pi 0 a Quad Core Mali 450 CPU (on the H5) and keep it below the $20 level. The closest cousin to the H5 is the Cortex-A53, which is a Quad Core 64Bit CPU used on the Raspberry Pi 3. This makes the O-Pi Zero Plus 2 (H5) a true 64bit system.
 
Here is a comparison of all the O-Pi Boards:
https://www.timewasters-place.com/orange-pi-boards-comparison-chart/
 
And prices of the O-Pi Zero based on AliExpress:
 
O-Pi Zero 256MB: $6.99 - https://www.aliexpress.com/item/New-Orange-Pi-Zero-H2-Quad-Core-Open-source-deve lopment-board-beyond-Raspberry-Pi/32760774493.html
 
O-Pi Zero 512MB: $8.99 - https://www.aliexpress.com/item/New-Orange-Pi-Zero-H2-Quad-Core-Open-source-512M B-development-board-beyond-Raspberry-Pi/32761500374.html
 
O-Pi Zero H3-512MB: $18.90 - https://www.aliexpress.com/item/Orange-Pi-Zero-Plus-2-H3-Quad-core-Bluetooth-min i-PC-Beyond-Raspberry-Pi-2-Wholesale/32799908030.html
 
O-Pi Zero H5-512MB: $19.90 - https://www.aliexpress.com/item/Orange-Pi-Zero-Plus-2-H5-Quad-core-Bluetooth-min i-PC-Beyond-Raspberry-Pi-2-Wholesale/32801249806.html
 
O-Pi 2G-IoT: $9.90 - https://www.aliexpress.com/item/Orange-Pi-2G-IOT-ARM-Cortex-A5-32bit-Support-ubu ntu-linux-and-android-mini-PC-Beyond/32802458477.html
 
And to believe, all this was because I thought the O-Pi Zeros I got I thought were H3 units. I was wrong, but they are still damn good little machines! Better than some of the more expensive units I have.
 
Live and Learn...