right, learning armv8 is only possible with a board starting at 750$ (without memory and requiring a lot of other stuff to buy, that probably double the price), but with x4 10 GBE SFP+ connectors, without such a load learning armv8 doesn't happen... no matter the arm core is the same cortex-a72. if you wanted to shock the OP, there are some ThunderX2 based machines, even hairier and pricier, but honestly such suggestions look like fart in the puddle.
ANT - my hobby OS for x86 and ARM.