Show HN: Terminal dashboard that throttles my PC during peak electricity rates

That's quite a beefy workstation you got there!

Yeah I don’t see anything that even suggests it throttles the PC.

Looks like it’s just a display.

Sorry, I only open sourced the dashboard part as mentioned in the bottom of the blogpost. Still working on improving the 'Power optimizer' service so will open source that soon as well.

All the modern CPUs will boost into high clockspeeds and voltage to get work done quicker but at considerably higher power draws per operation. On that side of the equation its clear that it uses more energy. The problem is the entire CPU package is on longer if you don't do that and this costs power too and so its a trade off between the two. Generally we consider there isn't much difference between them but I don't know about that having seen the insanity that was the 13th and 14th gen Intel's consuming 250W when 120W gets about 95% the performance I think its very likely moving down to power save and avoiding that level of boosting definitely saves small amounts of power.

Technology Connections just did a timely video on the very topic of power vs energy.

https://youtu.be/OOK5xkFijPc?si=Uya3fI5oy_JFfSqI

As with everything, it depends. If you are going to do the same jobs regardless of the amount of time it takes, then yeah, dropping the max power probably just spreads the energy use over time. That doesn't usually help you save money, unless you have a very interesting residential plan.

OTOH, if it's something like realtime game rendering without a frame limiter, throttling would reduce the frame rate, reducing the total amount of work done, and most likely the total energy expended.

It is well known in the PC hardware enthusiast community that the last few digits of percent of performance come at enormous increases in power consumption as voltages are raised to prevent errors as clock speeds go up.

Manufacturers chase benchmark results by youtubers and magazines. Even a few percent difference in framerate means the difference between everyone telling each other to buy a particular motherboard, processor, or graphics card over another.

Amusingly, you often get better performance by undervolting and lowering the processor's power limits. This keeps temperatures low and thus you don't end up with the PC equivalent of the "toyota supra horsepower chart" meme.

1400W for a desktop PC is...crazy. That's a threadripper processor plus a bleeding edge top of the line GPU, assuming that's not just them reading off the max power draw on the nameplate of the PSU.

If their PC is actually using that much power, they could save far more money, CO2, etc by undervolting both the CPU and GPU.

That's actually pretty cool. ESPs are awesome little things.

You’re probably already on top of it but if your company doesn't operate the datacenter you’ll also want to estimate the carbon cost of cooling in addition to the electricity that the machines consume.

Can you run the batch processing on other machines at off-peak hours?

Bring back the "turbo" button on the front of the PC.

Thanks! That's an excellent point. You're right that there's likely a sweet spot that would be more efficient overall than aggressive throttling.

The current implementation uniformly sets max frequency for all 128 cores, but I'm working on per-core frequency control that would allow much more granular optimization. I'll definitely measure aggregate consumption with your suggestion versus my current implementation to see the difference.

It's well established that completing the same task more slowly at a lower clock rate is actually less energy-efficient.

How is it with modern overclocked by default cpus? If you cut power use by 50% you still get 80% of the performance?

Good point. I'm often running multiple parallel jobs with varying priorities where uniform throttling actually makes sense. Many LLM inference tasks are long-running but not fully utilizing hardware (often waiting on I/O or running at partial capacity)

The dual Epyc CPUs (128 cores) in my setup have a relatively high idle power draw compared to consumer chips. Even when "idle" they're consuming significant power maintaining all those cores and I/O capabilities. By implementing uniform throttling when utilization is low, the automation actually reduces the baseline power consumption by a decent amount without much performance hit.

Thanks! I initially just wanted to build a dashboard, with the power optimization part being a later addition. Based on the HN response, it seems that's the feature that resonated most with people. I'll be making improvements to the optimization component in the coming days and will publish what I have.

The power optimizer daemon has only been running for a few days, so it's hard to measure in $ value but based on my peak pricing I would estimate the savings to be around a few dollars since then.

Definitely, I've been contemplating getting a 5-10kWh LFP battery backup with <10ms UPS switchover to run the workstation and home backup. This is an intermediate solution until then.

A cronjob would definitely work in most cases if the goal is just to auto change freq profiles during set ToU periods. I just wanted a more flexible system where the system can auto change the profiles based on actual utilization so demanding tasks aren't slowed down.

I'm on a time of use rate plan, most expensive from 11am-7pm. However they also have "Critical Peak Events" which increase the rate about 10x to over a $1/kwh that last up to 4 hours. Just saying it would be a bit more complex then just checking the time.