[tmurray]

but that's GLES 2.0, which is significantly less flexible than the kinds of GPUs we're discussing here and is not even in the same ballpark as a CPU (and almost certainly significantly less strict in terms of floating point precision than a GLES 3 device).

[kragen]

https://github.com/raspberrypi/userland/blob/master/host_app... is part of the Raspberry Pi GPU FFT example code. That is not GLES 2.0 or even GL of any kind. That's VideoCore QPU assembly language to compile with qasm. I haven't tried writing anything for it, but it certainly looks like it's "the kinds of GPUs we're discussing here" and "in the same ballpark as a CPU".

[sklogic]

Yet, it's pretty sufficient for things like FFT.