[milcron]

The Epiphany core is a co-processor, and the "main" processor is a couple of ARM cores to run Linux/other.

Maybe in the future they will offer boards with Risc-V main processors, and Epiphany co-processors.

I'm not sure how feasible 1024 Risc-V cores would be (although it sounds awesome). Epiphany cores were designed for this sort of thing.

[adapteva]

Agree, but people have all kinds of pre-conceived notions about co-processors so let's clarify some things: e5 can't self-boot, doesn't have virtual memory management, and doesn't have hardware caching, but otherwise they are "real" cores. Each RISC core can run a lightweight runtime/scheduler/OS and be a host.

[jecel]

Jan Gray stuffed 400 RISC-V cores into a Xilinx Kintex UltraScale KU040 FPGA (and the KU115 is three times larger, not to mention the Virtex UltraScale range).

http://fpga.org/grvi-phalanx/