With its 8 amps—more like 80A at typical core voltages—it retires potentially hundreds of billions of instructions per second. That is a long way from nothing in my book.
Well sure, but would you count that as actual "work" in terms of physics? I think not, at least not to any degree that should be notable.
There's no practical work being done in a CPU, it's just throwing away charge so it can redirect it around and do some calculations in the process, like a river flowing downhill with some mechanical logic gates in the stream.
The main problem I guess is that x64/x86 aren't designed for power efficiency as much as just pure speed. RISC does a lot better, and biological computers are on a few orders of magnitude more efficient. So there's definitely a lot of room for improvement.
