3 ms·
It can be a lot. Speculation requires executing operations before you're sure they'll be needed, which can double or triple power draw in order to increase inst
by tlb 4y ago
It can be a lot. Speculation requires executing operations before you're sure they'll be needed, which can double or triple power draw in order to increase instruction-level parallelism. And all the machinery needed to enable speculation, like branch predictors, draws power too.
This graph shows a factor of 100 between the highest-performing and most-efficient systems: https://en.wikipedia.org/wiki/Performance_per_watt#Examples https://en.wikipedia.org/wiki/Performance_per_watt#Examples
- ece 4y agoFor general purpose compute relying more on ILP than DLP, I would think the range is going to be narrower. Narrow enough to be a meaningful choice for consumers using battery powered devices and wanting more efficient or higher performance laptops and desktops. For servers, it seems like Intel and AMD are choosing optimizing more for perf/$ over perf/watt in their roadmaps. HPC roadmaps might be different still.