We can set the ARM cores' frequency higher than the 667 MHz limit.-- with GenZ, it's as easy as changing one parameter.
This demo uses the same bitstream as 3-emio, but the C program is modified to a blinky. Change the APU frequency in apu_oc.py and see how far your board can get!
I got up to 900 MHz with this simplest blinky and loading via JTAG. The power consumption seems to scale linearly with frequency.
Previously, overclocking (1.1G CPU and 750M DDR) has also been done in hz12opensource/libresdr, by directly modifying the EMIT_MASKWRITE arguments.