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Comment by SomeoneFromCA | Hacker News Reader

AMD CPU idle at high power, which kinda negates efficiency when loaded.Now their G series desktop CPU the opposite, idle very very efficiently.

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While the G series (basically mobile chips) do idle a lot lower, here's a chart that shows that Ryzen chips idle at about the same (a few watts less actually, but negligible) than their Intel high-end desktop counterparts: https://www.guru3d.com/review/amd-ryzen-7-8700g-processor-re...

One thing to keep in mind is that while slightly higher idle power might cost you a bit more, high power when processing means that you will also need a much beefier cooling solution and have higher noise levels and exhaust more heat to boot. Again, from the TechPowerup review https://www.techpowerup.com/review/intel-core-i9-14900ks/22.... they show that for a multi-threaded blender workload, the 7950X3D sits at 140W, while the 14900KS hits 374W. I don't believe there's a single consumer air cooler that can handle that kind of load, so you'll be forced to liquid cool (or go even more exotic).

I find a lot contradicting info about what the idle consumption of AMDs is, different graphs show different numbers (so I do not trust the source you've linked, as my own 12500 machine idles at about 25w) , but overall consensus on Reddit and other sources is that a typical AMD system will idle at +10 watts. compared to Intel. Some posts claim that idle dissipation for AMD (cpu only ) reaches 55w. My own exdperience with Ryzens (it was 3600 last time) is they indeed idle (and while lightly loaded too) at higher power. For my typical usage scenario, where 80-85% of times CPU does nothing it matters.

Definitely agree on the all over the place metrics for AMD. This is somewhat complicated by the chipset. The x570 chipset actually used like 7-8 extra watts over the x470 by itself because the repurposed i/o die turned into a chipset was the idle power using part of the CPU.

Different motherboards and settings are sort of a hidden factor in this in general it seems.

Don't ignore that "idle" isn't a real thing. Most Reddit users complaining about high idle consumption have a program causing the problem. For me, shutting down the Steam program took my Ryzen 3600 from 22 watts "idle" to 2 watts idle.

There is no such thing as idle in a modern desktop.

This problem also shows up in Intel's latest Meteor Lake laptop processors, which are supposed to be able to power off the CPU chiplet and idle with the two low-power cores on the SoC chiplet. In practice, most OEMs ship too much crapware on their laptops for that capability to kick in, and it's really hard to get Windows cleaned up enough to get the battery life the chip ought to provide.

LOL

For anyone that doesn't need the highest performance and where efficiency is super important, I can recommend the current generation of mini PCs/NUCs that run mobile chips. Last summer I picked up Ryzen 7 7940HS-based mini PC that idles at about 10W (from the wall), has a decent iGPU (the Radeon 780M is about on par with a mobile GTX 1650), and its 65W-max Zen 4 cores (8x) actually manages to be very competitive with my old custom 5950X workstation: https://github.com/lhl/linuxlaptops/wiki/Minisforum-UM790-Pr...

Intel Meteor Lake NUCs should perform similarly, but they tend to be a few hundred dollars more for basically the same performance (the Minisforum EliteMini UM780 XTX barebones is currently $440, the cheapest Core Ultra 7 155H minipc I could find was the ASRock Industrial NUC BOX-155H at $700). At this point though, personally, I'd wait for the upcoming Zen5/RDNA3.5 Strix Point APUs, which should be the next big jump up in terms of performance.

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