If there really is enough market demand for this kind of processor, it seems like someone like NEC who still makes vector processors would be better poised than a startup rolling RISC-V
The main product/architecture discussed has nothing to do with vector processors or riscv.
It's a new, fundamentally different data-flow processor.
Hopefully we will improve in explaining what we do and why people may want to care.
GreenArray processors are complete computers with their own memory and running their own software. The GA144 chip has 144 independently programmable computers with 64 words of memory each. You program each of them, including external I/O and routing between them, and then you run the chip as a cluster of computers.
One distinction of the GreenArrays chip is that they claim it is very energy-efficient.
Systolic arrays often (always?) have a predefined communication pattern and are often used in problems where data that passes through them is also retained in some shape or form.
For NextSilicon, the ALUs are reconfigured and rewired to express the application (or parts of) on the parallel data-flow acclerator.