How many 8-pin connectors are needed for Z690 motherboard

[wesel]

Hi,

I am planning to buy MSI Z690 Tomahawk DDR4 motherboard with 12700K CPU. Currently I am using an old Corsair HX750 PSU, which has only 1 8-PIN CPU connector. However on the motherboard there are 2 8-pin slots for the CPU. Still the CPU and PCI-E cables/connectors seem to be "equal".

So
1. do I need to buy a new PSU and
2. do I need to use both 8-pin connectors on the motherboard

The GPU is GTX 1080.

Thanks.

 

[tabascosauz]

For modern mainstream Intel and mainstream AMD, you should only ever need to plug in 1 of the 8-pins for any sort of normal use.

There is some speculation that some boards benefit from having both 8-pins plugged in for "cleaner power", but there's basically no real empirical evidence to back this up. Basically, if you have 2 on your PSU you may as well plug it in since whatever, but don't fret if the board has dual 8-pin but your PSU only has 1.

But do read your manual to see if they recommend which connector should be plugged in first. I have dual 8-pins on my Unify-X and it makes no difference which I use, but never hurts to make sure. So:

1. No
2. No

 

[wesel]

Thanks tabascosauz,

one more question - are PCI-e and CPU interchangeable? They do look different, but at the end the plugs seem to be same.

Thanks.

 

[tabascosauz]

No they are not physically interchangeable. Pins should be keyed differently, and obviously the connectors split differently into 4+4 and 6+2:

 

[wesel]

Understood.

Thanks again.

 

[Mussels]

Generally, one 4 pin will boot the board
One 8 pin is good for running pretty much every chip at stock
two 8 pins (or 12 pins from 8+4) is for overclocking high core count chips

12700k can spike to 234W (whole system!) according to the TPU review
4 pin supplies 155 watts, and the 8 pin supplies 235 continuous watts.

You can do the math yourself there (Remember the 234W was the entire PC at the wall, not CPU alone) and find out that at stock, you're fine with just 8 pins. 12 lets them run cooler, 16 more so.



I melted extensions on my RTX 3090 at 300W while the stock cables are fine, so thats another relevant topic: dont use extension cables, with that much power draw.


Edit: sauce
GPU and CPU power connections | Overclock.net

 

[tabascosauz]

@Mussels I couldn't find any concrete data on what modern 8-pin can take, but the OCN guide you're going off of is from 2014. I don't think the thick solid pin connectors existed back then, so 235W makes sense and was enough for quadcores.

All I can remember is that in the past billion Intel board breakdowns that have a 8+4 or 8+8, just constantly heard buildzoid saying that the solid pin 8-pin (these days much more the rule than the exception) can handle north of 300W or even 400W(?) CPU power. Maybe something like a H610 board I'd not be so sure whether it has the proper 8-pin, but Z690 should be universal (as it pretty much is on any decent B550/X570).

Here's one recent example, timestamp starts at 6:58 just in case the link doesn't work:

Unsurprisingly, Z690 Tomahawk has the same pins as like every other board these days so no issue there:

 

[bug]

Hi,

I am planning to buy MSI Z690 Tomahawk DDR4 motherboard with 12700K CPU. Currently I am using an old Corsair HX750 PSU, which has only 1 8-PIN CPU connector. However on the motherboard there are 2 8-pin slots for the CPU. Still the CPU and PCI-E cables/connectors seem to be "equal".

So
1. do I need to buy a new PSU and
2. do I need to use both 8-pin connectors on the motherboard

The GPU is GTX 1080.

Thanks.

This may be stating the obvious, but even when the PSU only has an 8 pin connector, it can still have an additional 4+4 or 6+2.

 

[Ferrum Master]

Having so much line in parallel not only help with OC, but vdroop, it is more efficient, mitigates protentional VRM noise issues as the added ground lines help to sink the electric noise to where it should and form correct loop, and not via motherboard standoffs for example. It applies for GPUs and CPUs.

It works without yea, but it never hurts to wire everything up as intended. The engineers had their ideas to spend the dollars to implement those. For a good reason.

 

[Mussels]

@Mussels I couldn't find any concrete data on what modern 8-pin can take, but the OCN guide you're going off of is from 2014. I don't think the thick solid pin connectors existed back then, so 235W makes sense and was enough for quadcores.

All I can remember is that in the past billion Intel board breakdowns that have a 8+4 or 8+8, just constantly heard buildzoid saying that the solid pin 8-pin (these days much more the rule than the exception) can handle north of 300W or even 400W(?) CPU power. Maybe something like a H610 board I'd not be so sure whether it has the proper 8-pin, but Z690 should be universal (as it pretty much is on any decent B550/X570).

Here's one recent example, timestamp starts at 6:58 just in case the link doesn't work:

Unsurprisingly, Z690 Tomahawk has the same pins as like every other board these days so no issue there:

lets put it this way: they havent gotten WORSE, and he's fine within the 2014 limits