Question which PSU cable goes where on the MB please

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angry.pidgeon

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Hello. Sorry about the newb post, but I'm completely newbie at modular PSUs and having trouble installing mine

I bought this PSU: be quiet! Straight Power 11 Platinum 750W
MANUAL:
My PSU is the one on the right in the picture on page 1 of the manual

And this MB: Asus TUF GAMING Z790

1. Problem: main power cable
1.1. it's straighforward where it plugs in the MB at one end
1.2. the other end in the PSU is a problem: it's separated into a 20 pin entry, and a 8 pin entry. The PSU has the 20 pin entry, and right underneath another 8 pin entry, both marked as "MB". Since this design is pretty counterintuitive, I don't know whether I should also connect the 8 pin entry underneath, or leave it unplugged. Manual is useless on both pieces of hardware on this matter. This video shows something similar, but refers to 24 pins, while I got 28:
View: https://www.youtube.com/watch?v=PXaLc9AYIcg
, so I still don't know for sure

2. Problem: secondary (CPU?) power cable. MB must take 2 x 8 pin connectors according to manual
2.1. Got 2 cables in the kit:

2.1.a. cable with 10 pins (middle ones missing actually) which connects to the only 10 pin slot in PSU. I guess that's it?
2.1.a.1 the other end same cable separates into a 1 x 8 pin connector named P8, and another 2x4 pin separated but bundled closeby, and named CPU1 - P4, CPU2 - P8. The only PSU slot also is named P8/P4. I have no idea which of the 2 motherboard 8 pin connector takes which end from these. The motherboard manual doesn't show these. These cable connectors also have clamps for the motherboard, which don't correspond to anything I can see on the motherboard slot, although I can push them in I think if I try

Motherboard manual:

2.1.b. cable with 10 pins at one end as the other, but only 2x4pins ending at the other, so I guess this is not it since the motherboard manuals sais I must connect 2 of 8 pins each. Again, CPU1 - P4, CPU2 - P8 is written on the 2x4 pins


3. The rest are 2 x VGA cables of 12 pins to 2x8 pins, which I guess connect to the GPU, and storage device and such which seem pretty straightforward, and have straighforward slots for them in the PSU
 
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Show photos of cables, you can't figure out.
(upload to imgur.com and post link)

Did you consult PSU user manual before asking here?
Yes. I said the manuals are useless on the matter (which you can check)

The pictures of the cables are in page 35 of the PSU manual, although my description is better (e.g. there's no 24 pin cable, there's a 20+8 pin cable, and one 20 pin PSU slot, and another 8 pin PSU slot underneath)

My PSU is the one on the right in the picture on page 1 of the manual
 
It might be best if you return the power supply and buy a model which supports 2 8-pin cpu connections since that is what your motherboard requires. If you do not connect those properly you should not expect your motherboard to function properly.
 
It might be best if you return the power supply and buy a model which supports 2 8-pin cpu connections since that is what your motherboard requires. If you do not connect those properly you should not expect your motherboard to function properly.
Nah, I won't wait for another, plus this is a good one, I just don't know how to use it

I just read that one 8 pin connection is enough, even if I OC at 5Ghz, but I still want to use 2x8 pin for stability they say. This PSU actually uses backward compatibility for my motherboard even if new, that's how advanced it is

Also if I read the manual correctly, all those connectors deliver the same power so I can't mess up, there's no wrong order

Still, I'm going to wait for someone's knowledgeable advice before I blow everything up :)
 
The pictures of the cables are in page 35 of the PSU manual, although my description is better (e.g. there's no 24 pin cable, there's a 20+8 pin cable, and one 20 pin PSU slot, and another 8 pin PSU slot underneath)
Your descriptions are rather convoluted and hard to follow.
Providing photos of your cables would be much more effective.

Anyway ... lets try to understand, what you're describing there.
1. Problem: main power cable
1.2. the other end in the PSU is a problem: it's separated into a 20 pin entry, and a 8 pin entry. The PSU has the 20 pin entry, and right underneath another 8 pin entry, both marked as "MB". Since this design is pretty counterintuitive, I don't know whether I should also connect the 8 pin entry underneath, or leave it unplugged.
Both plugs (20pin and 8pin) go into PSU. Sockets on PSU are labeled MB.
2. Problem: secondary (CPU?) power cable. MB must take 2 x 8 pin connectors according to manual
2.1. Got 2 cables in the kit:

2.1.a. cable with 10 pins (middle ones missing actually) which connects to the only 10 pin slot in PSU. I guess that's it?
2.1.a.1 the other end same cable separates into a 1 x 8 pin connector named P8, and another 2x4 pin separated but bundled closeby, and named CPU1 - P4, CPU2 - P8. The only PSU slot also is named P8/P4. I have no idea which of the 2 motherboard 8 pin connector takes which end from these.
Use this cable, if motherboard requires two 8pin CPU 12V cables (your situation).
4+4 plug makes another 8pin CPU 12V plug.

2.1.b. cable with 10 pins at one end as the other, but only 2x4pins ending at the other, so I guess this is not it since the motherboard manuals sais I must connect 2 of 8 pins each. Again, CPU1 - P4, CPU2 - P8 is written on the 2x4 pins
Use this cable, if motherboard requires 4pin CPU 12V cable or single 8pin CPU 12V cable.
One end (10pin) goes into PSU (labeled P4/P8), other end goes into motherboard.
3. The rest are 2 x VGA cables of 12 pins to 2x8 pins, which I guess connect to the GPU, and storage device and such which seem pretty straightforward, and have straighforward slots for them in the PSU
Use those for graphics card. Depending on power requirements of the card use necessary amount of cables.
 
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Both plugs (20pin and 8pin) go into PSU. Sockets on PSU are labeled MB.

Use this cable, if motherboard requires two 8pin CPU 12V cables (your situation).
4+4 plug makes another 8pin CPU 12V plug.

Use this cable, if motherboard requires 4pin CPU 12V cable or single 8pin CPU 12V cable.
One end (10pin) goes into PSU (labeled P4/P8), other end goes into motherboard.
Yes, basically I'm asking for confirmation that I'm not going to blow anything up by plugging it wrong :)

Pics means taking with phone, putting online, getting links and editing... too much work :) Pictures won't help except if you can't imagine it. My 20 + 8 connector looks like the 20 + 4 connector, that is 10 pins over another row of 10 pins, then in another bunch, 4 pins over 4 pins, or 2 over 2 respectively. Only question is whether I'm suppose to plug in the separate 8 or 4 bundle of pins

I emailed both Asus and be quiet! support (their site is down, that's promising...). I'll wait for 12 hours and consider before I plug things in, but I'm starting to build confidence. Why can't this be straightforward...
 
Got another thread that confirms my other findings, except nobody defines what is "heavy overclocking" in Watts. To me even the factory default of going from 3.2 Ghz to 5.1 Ghz is pretty heavy, a 59% overclock. On the other hand I've googled OCs up to 100% hmmm

* that guy's PSU even weirder than mine

On this youtube at 3:20 the guy also sais "not needed right now", not being concerned whether if there is a problem plugging into the 2nd slot or not
View: https://www.youtube.com/watch?v=rucfmsGjPow
 
Pics means taking with phone, putting online, getting links and editing... too much work

Pictures won't help except if you can't imagine it.
In other words you don't really want help here. The posters here are volunteers, they owe you nothing and if you want to waste their time they will leave to go help someone else who's a little more willing to work with them. No one here can see your system so they must rely on you to provide every single piece of information, including pictures. If you aren't willing to work with them then this thread becomes useless and will be closed accordingly. Unless, of course, you decide to work with those trying to help you. The ball is in your court.
 
I wish not working would be the only possible scenario, because then it's an easy fix. But if I fry anything it's done for :)
Your second problem is the CPU cable which is an 8pin and 4+4pin cpu power on the same cable. when the 4+4 is put together correctly it has the same pinout as the 8pin so you can use both connectors in the 2x 8 pin connectors on your board does not matter which one where since basically the same connector.
Frying stuff happens when people use the wrong connector like plugging PCIe into CPU and wise versa

You got two CPU cables and one is for a single connector and the other one is for two connectors be it 8+4 or 8+8 like you have this is because your PSU only has one CPU out connector.
 
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It might be a good idea if you took your rig round to a friend's house (if they're familiar with building PCs) or to a local computer shop.

Connecting an ATX PSU to a motherboard is a 5 minute job (less if it's not fully modular) but if you get things wrong, BANG.

Save yourself a lot of grief and get some local help.
 
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