[ndriscoll]

I was under the impression that AMD desktops/home servers generally don't go below 15-20 W, while Intel can get down to 4-6 W idle for the full system. Has that changed? AMD seems to generally be the better perf/$, but I thought power usage at idle was their big drawback for desktops/low-usage servers.

IIRC the numbers I've read are that (at least desktop) Intel CPUs should be using something like 0.2 W package power at idle if the OS is correctly configured, regardless of whether it's a performance (K) or "efficiency" (T) model. Most power usage is the rest of the system.

[hnuser123456]

https://en.wikipedia.org/wiki/Cool%27n%27Quiet

They both have similar frequency and voltage scaling algorithms at this point. You will probably not see 0.2W idle though, both probably idle around 10W on desktop and 5W on laptop. But Intel is getting much more aggressive with "turbo boost" to try to hide their IPC/process deficit vs. AMD/TSMC, to the point that a 14900k will use 120W+ to match the performance of a 7800x3d at 60W.

[ndriscoll]

As far as I can gather, that's not the case. These guys[0] have been crowdsourcing information about power efficiency for a while now, and the big takeaways right now seem to be that

* Intel is the best for idle (there's several people that have systems that run at less than 5 W for the full system using modified old business minipcs off ebay). Allegedly someone has a 9500T at less than 2 W full system power.

* It doesn't matter which Intel processor you use; all of them for many years will get down to 1 W or less for the CPU at idle. A 14900K will idle just as well as an 8100T, which will be much better than a Ryzen 7950X.

* AMD pretty much never gets below 10 W with any of the Ryzen chiplet CPUs. Only their mobile processors can do it, but they don't sell them retail and they're usually (always?) soldered.

* Every component except the CPU is more important. Your motherboard and PCIe devices need to support power management. You need an efficient PSU (which has nothing to do with the 80-plus rating, which doesn't consider power draw at idle). One bad PCIe device like an SSD or a NIC can draw 10s of watts if it breaks sleep states. Unfortunately, this information seems to be almost entirely undocumented beyond these crowdsourcers.

For a usually idle home-server, Intel seems to be better for power usage, which is unfortunate because AMD tends to have more IO and supports ECC.

[0] https://www.hardwareluxx.de/community/threads/die-sparsamste...