Raspberry Pi interview: Eben Upton reveals all (Linux User)

Exactly right. Be learned this the hard way when they created an entire computer around an AT&T Hobbit DSP. The microbenchmarks were mind-blowing so people were surprised when the OS as a whole felt really sluggish and no amount of optimization helped. You're dead in the water if you can't keep the pipelines full. And DSPs and GPUs have absurdly large pipes.

I don't know if others have learned this lesson the hard way but, since the 80s, who hasn't thought at one time or another, "holy crap, look at the throughput on that sucker!! No need for a CPU!"

The convergence is happening but it's taking longer than most people would have guessed.