Possible to lower 12900ks base clock ??

[digitaldreams]

Looking to the future beyond my 12900ks I see the 13900kf, 13900ks and a possible refresh lga1700 later this year (or not). Note I'm not just considering my PC (sig) but my sons too who will inherit my kit when I improve my motherboard.

Getting a little more performance from video encoding etc, lowering idle power consumption and later moving to DDR5-5600 from DDR4- 3200/3600 with a newer Z790 motherboard make the 13900kf an interesting first move forward. The 13900ks seems of little or negative value with its crazy heat and power consumption.

The 13900kf features and benefits raise a question though. With my current system, could I easily lower the base clock frequency of my 12900ks in the ASUS bios without affecting any other settings ?. The pc is sometimes left downloading large files or just internet browsing and a power drop would be great !.

 

[Tetras]

With my current system, could I easily lower the base clock frequency of my 12900ks in the ASUS bios without affecting any other settings?

The base clock of 3.4 Ghz should be very efficient, I don't think you would want, or need to lower this any further. If you did, I suspect the responsiveness and gaming performance would drop off considerably. The easiest way to manage the power and clocks is just to change the power limits in the BIOS, you may be interested in this article:

A Lighter Touch: Exploring CPU Power Scaling On Core i9-13900K and Ryzen 9 7950X

www.anandtech.com

I assume you're aware that forcing the CPU to stay at base clock means disabling turbo mode. With high-end CPUs it can help with the high power consumption and voltages in some circumstances, but disabling turbo mode is definitely the sledgehammer solution and can be pretty impactful on performance.

The pc is sometimes left downloading large files or just internet browsing and a power drop would be great !.

It should automatically manage the clocks and power draw according to demand, unless you have a high performance power profile enabled, or a custom overclock. If your CPU is pegging multiple cores at high clocks and using a lot of power with such menial tasks then I'd try updating the LAN/WIFI and chipset drivers.

 

[digitaldreams]

The base clock of 3.4 Ghz should be very efficient, I don't think you would want, or need to lower this any further. If you did, I suspect the responsiveness and gaming performance would drop off considerably. The easiest way to manage the power and clocks is just to change the power limits in the BIOS, you may be interested in this article:

A Lighter Touch: Exploring CPU Power Scaling On Core i9-13900K and Ryzen 9 7950X

www.anandtech.com

I assume you're aware that forcing the CPU to stay at base clock means disabling turbo mode. With high-end CPUs it can help with the high power consumption and voltages in some circumstances, but disabling turbo mode is definitely the sledgehammer solution and can be pretty impactful on performance.



It should automatically manage the clocks and power draw according to demand, unless you have a high performance power profile enabled, or a custom overclock. If your CPU is pegging multiple cores at high clocks and using a lot of power with such menial tasks then I'd try updating the LAN/WIFI and chipset drivers.

Yet the lower base clock of the 13900kf seems to have lowered the idle power somewhat compared to the 12900ks !. I'm not aware of anyone reporting lower responsiveness in the 13900kf due to lower base clock (virtually identical technologies too), I expect gaming would usually result in frequencies higher than base.... Thanks for the link, will look asap

 

[Tetras]

Yet the lower base clock of the 13900kf seems to have lowered the idle power somewhat compared to the 12900ks !. I'm not aware of anyone reporting lower responsiveness in the 13900kf due to lower base clock (virtually identical technologies too), I expect gaming would usually result in frequencies higher than base.... Thanks for the link, will look asap

I think we're using different terms to mean different things.

Intel's definition of base clock is the stock frequency without turbo and it is pretty much never used in reality. The base clock has nothing to do with idle power, because the CPU doesn't idle at the base clock.

I suspect the reason it is lower (not that it matters, because like I said, it's not actually used in reality) is just because the 13900K/KS have 16 E-Cores, whereas the 12900K/KS only has 8, so it needs a lower clock to stay in the stock power envelope.

Turning off the turbo and running at base clock usually puts the CPU in a very power efficient state for the architecture and I'm not talking about 12th vs 13th gen, only if you choose to manually disable turbo mode for efficiency reasons. I do this all the time and it does have an impact on responsiveness and gaming performance, but that applies to any midrange/high-end CPU when turbo is disabled. How much of an impact depends on what you do with the PC, the impact is less gaming at 4K than 1080p, for example.

 

[digitaldreams]

Yet 13900KF TDP PL1 is 125W vs 12900KS 150W ?. Suggests the 13900 does use less power at idle !

 

[Tetras]

Yet 13900KF TDP PL1 is 125W vs 12900KS 150W ?. Suggests the 13900 dies use less power at idle !

The KS is a special CPU which is pushed harder than normal, so the power limits aren't directly comparable to the K/KF.

But, PL1 is not relevant to idle power, because as a said in my earlier post, no CPU idles at the base clock.

It's quite hard to get reliable idle figures, because they often use different systems in reviews and the motherboard/PSU have a big influence, as does the BIOS version and how the BIOS is configured, but I generally find computerbase.de one of the most reliable (for power consumption) and here are some of their figures (link):

Idle (whole PC), watts
42 - i5-12500 (DDR4-3200)
43 - i5-12400 (DDR4-3200)
54 - i9-12900K (DDR5-4400)
54 - i7-12700K (DDR5-4800)
54 - i5-12600K (DDR4-3200)
56 - i9-13900K (DDR5-5600)
56 - i9-12900KS (DDR5-4400)
56 - i7-13700K (DDR5-5600)
56 - i5-13600K (DDR5-5600)

The discrepancy between the 12400/12500 and 12600K despite (I assume) using the same board/memory, I suspect is because of the H0/C0 thing, which you can see in the testing hwcooling.net did here:

CPU-only, average idle power, watts
14.73- i5-12400 (H0)
16.75 - i3-12100F (H0)
22.54 - i9-12900K (C0)
25.46 - i5-12400 (C0)

hwcooling.net, from a later review:

CPU-only, average idle power, watts
16.75 - i3-12100F
21.09 - i9-13900K
22.54 - i9-12900K
25.46 - i5-12400 (C0)

I'd guess there's around a 1-2 watt variance between dies of the same architecture (regardless of how many cores are enabled/disabled), on average.