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by blattimwind 2169 days ago
> I used a Satechi USB-C power tester and measured an 8% peak power savings using UASP. That means you'd get 8% more runtime on a battery if you do a lot of file transfers.

No no, even better! Peak power consumption is lower, but the same work is completed much more quickly due to increased throughput, so the energy required for the same work is decreased dramatically. Between the performance increase and the lower power usage I wouldn't be surprised if this reduces energy use by 50 %.
3 comments
repsilat 2169 days ago
Yeah. This kind of savings comes up in interesting places elsewhere -- if you make your algorithm run twice as fast but using twice the memory, your time-integrated memory use (measured in gigabyte seconds) remains the same. So if you can make good use of that memory while your algorithm isn't running, you're saving CPU and not really using more RAM.

For something like the Pi this is unlikely, but in data centers with big, latency-insensitive distributed workloads "using memory for less time" can be a real win. (The battery example with the Pi really is the perfect example though, because you're usually interested in the time-integrated value more than the peak draw.)

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geerlingguy 2169 days ago
It depends a lot on the workload, though. That kind of statistic is hard to draw any solid conclusions from, except that “it uses less CPU and less overall power during IO activity” and you’ll save some amount of energy consumption (depending on what you’re doing).
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asudosandwich 2169 days ago
https://en.wikipedia.org/wiki/Amdahl's_law
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