I'm rather surprised at the claim that "but it might easily execute 7 billion instructions per second on a single core". I'd even question it except the author's an expert.

If you can keep it fed then ok but one cache miss to main mem, either instruction or data, will allow the instruction buffers to completely empty and stay empty for quite a long time. I don't think you can control placement to reasonably assure cache hits always for anything but the most trivial code, am I missing something?

Also if you could keep a consistent throughput like this I wonder if thermal throttling might have to kick in. I mean you're doing a lot of work...