3 ms·
Because clockspeed ramps power exponentially, there’s a limit to how high you can clock before the cost of racing outweighs the savings of running a short time.
by hajile 2y ago
Because clockspeed ramps power exponentially, there’s a limit to how high you can clock before the cost of racing outweighs the savings of running a short time.
I believe I’ve read that Apple’s chips run under 3GHz unless their job runs longer than 100-150ms. I suspect that’s their peak race to sleep range.
- monocasa 2y agoClocks aren't the only way to race. Powering up the massive core with it's over a dozen pipelines, massive reorder buffer, etc. is another way. This is they way Apple has chose to focus on.
- oasisaimlessly 2y ago> Because clockspeed ramps power exponentially It's not exponential; P = C V^2 f, so power is something between O(f) and O(f^3), depending on how voltage scaling works. It follows that efficiency (energy per instruction) is something between O(1) and O(f^2).