Do B-series motherboards take less power than Z-series boards?

[lpwin7]

Hi, I posted while back about building a low power PC. I did get some parts together and I got some good results with an i5-13600k in terms of low power at idle. (I will make a separate post about my setup and power savings later.) My problem is that I seem to be having a possible compatibility issue between my ram and motherboard. I currently have a gigabyte b660m (and b760m) gaming x ax, which is very good in terms of power usage and it has decent VRMs and no extra bullshit features that would use extra power. I got this board because this forum basically said "b series boards will take less power" but I wanted to explore that idea. Why is it that b-series boards take less power? (Is it just because default bios settings tend to be more conservative?) If I get a z-series board with features similar to the board I have now, could I turn down the bios settings and have it use the same amount of power as a b-series board?
Thank
you!

 

[DJMadMax]

I got some good results with an i5-13600k in terms of low power at idle

I'm curious, post some numbers Would love to compare with my 12600k, Z690 and RTX 3060 Ti at idle.

I currently have a gigabyte b670m gaming x ax

B660M I guess? Or B760M? There is no B670 chipset, neither said Mainboard.

Why is it that b-series boards take less power?

You already figured it out yourself. B660/760-chipsets feature a few less I/O and other third party chips, so it's obvious, a lesser feature packed board will draw less power, hence the rest of the hardware and settings are identical.

Plus: Z-boards dont offer any features over B (or often even H) chipsets from what a typical user (e.g. gamer) would benefit in any way.

 

[KnolleJupp]

The B760 chipset has a TDP of 6W same as the Z790 chipset. There is no difference.

Less power consumption results through different configurations or equipment of the motherbords.
Cheaper or simpler mainboards are equipped with less or simpler features. Less internal or external connections, less additional controllers etc.

This leads to a lower energy consumption. There are simply fewer electronic components available on that mainboards that can consume energy.

Maybe the weaker power stages for the CPU power supply have a better energy efficiency while running at a low energy load.
But I'm not sure about that.

There should be no difference in power consuption when using the same CPU.
Your i5-13600K has a TDP of 125W up to 181W no matter what mainboard you are using.

Some of the better Z790 mainboards use overclocking settings by default. I mean the PL1, PL2, TAU, voltage etc. settings.
Cheaper mainboards use more often Intels stricter manufacturer specifications.

The power stages and BIOS features used on non Z mainboards are not designed and don't have to be designed for overclocking
because it's just not possible to overclock the CPU with that chipsets.

 

[TriceO]

Motherboard manufactures might be a bit over-enthusiastic with default settings for voltage and current-settings on "Gaming" Z-Boards. Thats why identical CPUs get different benchmark numbers on different boards.
But in theory, you should be able to get identical values by using manual settings.

Personally I'm curious why you've chosen a 13600k for a low power consumption PC. I've thought the 13500 is the sweet spot.

PS: are you sure it's a compatibility problem oder might it be faulty module(s)?

 

[lpwin7]

I'm curious, post some numbers Would love to compare with my 12600k, Z690 and RTX 3060 Ti at idle.


B660M I guess? Or B760M? There is no B670 chipset, neither said Mainboard.


You already figured it out yourself. B660/760-chipsets feature a few less I/O and other third party chips, so it's obvious, a lesser feature packed board will draw less power, hence the rest of the hardware and settings are identical.

Plus: Z-boards dont offer any features over B (or often even H) chipsets from what a typical user (e.g. gamer) would benefit in any way.

Uh to clarify, I actually tried the Gigabyte GXAX B660M and B760M (Had to pick up an extra for troubleshooting.) I will correct my post, thank you.

And yes, I am looking forwards to posting some numbers once I get it fully working and tested!

 

[lpwin7]

Motherboard manufactures might be a bit over-enthusiastic with default settings for voltage and current-settings on "Gaming" Z-Boards. Thats why identical CPUs get different benchmark numbers on different boards.
But in theory, you should be able to get identical values by using manual settings.

Personally I'm curious why you've chosen a 13600k for a low power consumption PC. I've thought the 13500 is the sweet spot.

PS: are you sure it's a compatibility problem or might it be faulty module(s)

First, I agree that it may be faulty modules. I had written down all the voltages and subtimings that were booting correctly, but at some point those same settings stopped working. So far I have tried a duplicate motherboard, duplicate CPU, and pulling a similar wattage PSU from my current/old desktop PC. Nothing helped. So I am returning RAM and the duplicate CPU, and the new RAM should ship this week.

About the 13600k. My old desktop has a 4670k and I've been using it 12 years. I am very poor, whatever I buy has to be able to last a long time. Plus I have to get the best deal for the money, which in this case was $250 USD for the 13600k using Best Buy price match again Microcenter's $250 price from a couple months ago. I could have got a lesser CPU for the same cost or maybe slightly more money depending on which ones I was looking at (I was also considering 12400, 12600k, etc.) As long as the 13600k can idle low (also very low while browsing the net and watching 1080p Youtube), which it absolutely does ( and I will post results and proof in the coming weeks), I can use undervolting, power limiting, core parking, etc. for when I am putting the CPU under more load when I want to use less power and generate less heat. But it can also hit the gas when I want to play a game!

 

[g0l3m]

I have these CPUs in 2 of our computers (13500 +13600k) and I have both chipsets (B660 + Z690). Every CPU is able to idle at low voltages so the system power consumption is low too for both pcs. Without optimization there is no difference in power consumption between B660 and Z690!

My observations: First I've built the 13600k with a B660 Mainboard. It war difficult to cool the cpu in high load scenarios. It drained ~165 Watt in Cinebench R23 despite of undervolting. With even more undervolting steps the performance decreased, so I was not able to go lower than 165 Watt without performance loss.

So I tried a Z690 chipset and after disabling the Intel undevolt protection options (IA CEP + CPU Under Voltage Protection => MSI Board) in UEFI I was able to push my 13600k down to 145 watt at full performance (~24.300+ points at Cinebench R23). Finally I disabled 2 E-Cores and overclocked the single core boost slightly. So now I'm at 6p/6e/6t ~128 Watt with 22.000 points at Cinebench R23.

For the 13500 I disabled 2 E-Cores too, the CPUs sits in a H670 Board, so undervolting is with limits only possible. It computes ~19350 points at Cinebench R23 with a power drain of ~125 Watt too, equal to undervolted 13600k. So at the same power consumption is my 13600k about 13% faster than the 13500. The 13% doesn't matter for me, more important for me is to stay as low as possible in terms of power consumption for every PC here. Practical aspects are environment temperature, cooler noise and costs.

So if you plan to go with the lowest possible power drain go with a Z-Chipset to unlock all options for undervolting, especially if you owned a K-CPU.

 

[TriceO]

I could have got a lesser CPU for the same cost or maybe slightly more

Your choice is totally understandable; especially for this long-term investment. If you can get a faster CPU for less money then you take it.

I was curious where you are going with this thread in terms of "building a low power PC" as I once had a knack for low-consumption PCs too. Now I've thought that the 13500 has the better ratio in terms of performance for watt.
But sure, the 13600K is faster.
And thanks to @g0l3m delivering the perfect answer and testing both chipsets and both mentioned CPUs, we see that with tweaking the K is the better choice.