[Ryzen Mobile] 6 cores vs 4 in terms of power efficiency, need clarification

[TECH J]

Hey, i have a ryzen 5 5625u laptop, and i want to maximize power efficiency.

Should i leave all cores enables with the power plan set to "BEST POWER EFFICIENCY" or should i disable 2 out of 6 cores and stick with the same power plan?

I am asking because there is a possibility if i disable 2 cores, the other 4 will work harder -> higher power consumption than leaving all of them on.. Not sure how effective is core parking in action..

[Naijin]

10 minutes ago, TECH J said:

Hey, i have a ryzen 5 5625u laptop, and i want to maximize power efficiency.

Should i leave all cores enables with the power plan set to "BEST POWER EFFICIENCY" or should i disable 2 out of 6 cores and stick with the same power plan?

I am asking because there is a possibility if i disable 2 cores, the other 4 will work harder -> higher power consumption than leaving all of them on.. Not sure how effective is core parking in action..

Why not test it?

Use hwinfo or anything else to read core frequency and power draw, then compare them. Maybe just try idle on desktop/chrome and Cinebench.

[TECH J]

1 hour ago, Naijin said:

Why not test it?

Use hwinfo or anything else to read core frequency and power draw, then compare them. Maybe just try idle on desktop/chrome and Cinebench.

i want to but i don't currently have much free time, that's why i am asking if someone else have already test something similar

[ki8aras]

2 hours ago, TECH J said:

i want to but i don't currently have much free time, that's why i am asking if someone else have already test something similar

idk man thats a very specific question youre asking

[Roasted_Hobnail]

On 6/12/2023 at 8:56 AM, TECH J said:

Hey, i have a ryzen 5 5625u laptop, and i want to maximize power efficiency.

Should i leave all cores enables with the power plan set to "BEST POWER EFFICIENCY" or should i disable 2 out of 6 cores and stick with the same power plan?

I am asking because there is a possibility if i disable 2 cores, the other 4 will work harder -> higher power consumption than leaving all of them on.. Not sure how effective is core parking in action..

Hello!

Modern CPUs have extremely sophisticated power-management features built-in, especially modern AMD ones. By disabling in-software processor cores, which is not "disabling" strictly speaking, but is called "parking", you're trying to override those features. On idle, all modern CPUs put their cores and other silicon parts to deep sleep automatically - by using a mechanism called C-states. Have a read of this guide about optimizing battery life on Windows. It is mainly focused on Intel processors, but the techniques and software described there may come in handy in your case as well.

Simply put, you will most likely not only gain nothing but rather lose performance AND battery life by simply disabling the "unnecessary" cores. Also, you might want to read this whitepaper from Intel. It's pretty old, but the main principles work to this day. One important part that's mentioned there - bursty workloads and their impact on CPU power consumption. According to this paper, it is more efficient to wake up ALL cores, finish the load as quickly as possible, and then put the entirety of the CPU package (iGPU, Uncore, various controllers, etc) back into deep sleep states.

Should you have any questions, don't hesitate to ask

Edited July 8, 2023 by Roasted_Hobnail
Incorrect link