New PCI-E pin on Motherboard

[serein]

While checking the motherboards, I noticed an additional PCIe power connector. Is it because the graphics card might draw more power than the motherboard? But hasn't it already drawn power from the additional connectors? Is this a new installation requirement, or is it optional?

 

[eidairaman1]

While checking the motherboards, I noticed an additional PCIe power connector. Is it because the graphics card might draw more power than the motherboard? But hasn't it already drawn power from the additional connectors? Is this a new installation requirement, or is it optional?

View attachment 381654

Find the motherboard manual on the makers website, read it, it will explain everything you need to know.

 

[TheLostSwede]

See this news post for a bit more info. It's still not clear to me what it's for.

MSI Unveils the World's First ATX 3.1 Ready Motherboards, Based on AMD's X870/X870E Chipset

MSI is thrilled to introduce a groundbreaking feature on its X870(E) series motherboards. This innovative is designed with gamers and professionals in mind, provides the extra power required for AI computing and GPU-intensive applications. The supplemental PCIe Power feature, equipped with an...

www.techpowerup.com

 

[Harlow]

From the link above:

"Usually, the motherboard's 24-pin 12 V power connector can only supply a maximum of 168 W."

When you plug a GPU card into the motherboard, it can draw up to 75W from the PCIe x16 motherboard socket. That leaves 93W for everything else (not including the CPU and RAM supplied from separate ATX12V connectors).

If you plug more PCIe cards into the computer, they will draw additional power from the PCIe slots. Add the power required for multiple 12V case fans, AIO pump, radiator fans, plus RGB lighting and the 168W limit could be reached.

As the article says:

"That's where MSI's 8-pin Supplemental PCIe Power Connector steps in. On the MAG X870 TOMAHAWK WIFI, this additional connector provides up to 252 W of extra power, ensuring everything have enough power to run at their full potential. The 24-pin and 8-pin connectors deliver a combine total of 420 W, giving the entire system plenty of power headroom to operate smoothly, even under the most demanding conditions."

If you feel the need to install 12 case fans, a 360mm AIO pump and radiator, loads of RGB bling, a GPU and additional PCIe cards, that extra 8-pin power motherboard power input becomes handy.

 

[londiste]

66W for 12V from PCIe slot. Which is a nitpicky point, I know.
But before thinking fans and RGB I look at the board picture in the first post and there are 4 PCIe x16 slots. Each of them wanting 66W would need 264W already.

 

[Ruru]

I remember ~20 years ago seeing molex connectors on the first SLI capable motherboards, but I never heard that they were actually neccessary. I guess that they're just for "better safe than sorry" kind of situations.

 

[Chrispy_]

Plenty of boards existed back during the transition from Intel's P4 connector to the 8-pin EPS connector we now use - so many boards had both a P4 and EPS connector.

I read the odd motherboard manual when I first encountered them, and it seemed to be originally introduced for compatibility reasons - use the EPS socket if your PSU has a 4+4pin or 8pin plug, but use the 4-pin if your PSU only has the old P4 plug.

As CPUs needed more power, boards started using the dual sockets in tandem, so you had 8-pin EPS and the P4 connector, for a total of 6x 7A pairs (504W). Now we have boards like OP's that use dual 8-pin EPS which is theoretically 8x 7A pairs (672W)

My question is whether it matters which EPS socket you plug your single EPS connector into, when you don't need 672W of power to your motherboard?

Also, that question is specific to dual-EPS boards - I know MSI has started throwing a GPU's PCIe 8-pin socket up there next to the EPS socket in some of its latest models. In theory that's fine because the MiniFit Jr connectors for EPS and PCIe are keyed to be incompatible, but I guarantee you someone will flashbang themselves after brute forcing an 8-pin EPS plug into an 8-pin PCIe power socket!

I remember ~20 years ago seeing molex connectors on the first SLI capable motherboards, but I never heard that they were actually neccessary. I guess that they're just for "better safe than sorry" kind of situations.

Also an MSI first, I think.
DFI joined the party a little later, too.

 

[Jawz]

Manual is actually pretty sparse on info on this. The main product page from MSI states:

"PCIe supplemental power​

The exclusive Supplemental PCIe Power connector provides dedicated power for the high-power demands of GPUs used in AI computing and gaming, ensuring stable, efficient, and sustained performance."​

Also provides a link regarding case compatibility that also states

"MSI adds extra PCIE_PWR1 connector on motherboard bottom side for better system stability when using multiple or power hunger PCIe devices.​

It is recommended to connect PCIE_PWR1 to power supply under such scenario and the extra space is advised for easy PCIe power cable insertion."​

Overall, they're vague on what it's for other than for extra power, just in case, as others have suggested above.

 

[Chrispy_]

Manual is actually pretty sparse on info on this. The main product page from MSI states:

"PCIe supplemental power​

The exclusive Supplemental PCIe Power connector provides dedicated power for the high-power demands of GPUs used in AI computing and gaming, ensuring stable, efficient, and sustained performance."​

Also provides a link regarding case compatibility that also states

"MSI adds extra PCIE_PWR1 connector on motherboard bottom side for better system stability when using multiple or power hunger PCIe devices.​

It is recommended to connect PCIE_PWR1 to power supply under such scenario and the extra space is advised for easy PCIe power cable insertion."​

Overall, they're vague on what it's for other than for extra power, just in case, as others have suggested above.

My guess is that it's for people who are using PSUs that don't have two EPS connectors. I don't see the need to have dual-EPS and 8-pin PCIe power all simultaneously.

If you add that up:
336W EPS1
336W EPS2
168W 24-pin ATX
+ 150W PCIe 8-pin
------------------
= 990W

That's overkill for even the most ridiculous configuration of 4x PCIe card drawing 66W each, a CPU with aggressive PBO+ that's double the stock PPT (340W), and some fans.

 

[Flaky]

On most motherboards, CPU 12V and ATX 12V rails are separate, so it won't add up like that.
This makes it easy to go over power budget on 24pin alone if multiple full-sized PCIe cards are installed.

 

[Chrispy_]

On most motherboards, CPU 12V and ATX 12V rails are separate, so it won't add up like that.
This makes it easy to go over power budget on 24pin alone if multiple full-sized PCIe cards are installed.

So this is entirely for PCIe slots and silly RGBLED?