Corsair AX850 Gold PSU, Asus Z590 Mobo, and Nvidia RTX 3070Ti build question.

[TigerWoody76]

I have a older Corsair AX850 Gold Power Supply and all the modular cable connections on the back of the PSU are full except for a 8 pin connecter (see photo).  After doing research I believe that this 8 pin connector is for a CPU, but my motherboard is already connected powerwise by the 24-pin ATX 12v on the right side of the board and a 8-pin ATX 12v (ATX-12v-1) on the top left side of the board, both are separate modular PSU cables (a 4-pin connection, ATX-12v-2) next to this is vacant - is this suppose to be correct?).  PC seems to power on ok. I also have an extra 8-pin AX850 cable that splits into two 4 pin connections (marked CG01).  Does this go into the vacant 4 pin connection (ATX-12v-2)  next to the 8 pin ATX 12v connection (ATX-12v-1)?

 I recently upgraded from a RTX 2070 Founders to a RTX 3070Ti, and like everyone else, realized there are 3 PCie 8 pin connections on the card, instead of 2 on my old card.  Two of the PCIe connections are connection by a single AX850 12pin to a dual pigtailed 6+2 PCie connection (was told by some you shouldn't use a pigtailed PCIe Cable?).  Anyone know if Corsair makes a 8 pin connector to PCIe to plug into my third PCIe slot on my 3070?  As of now I have a Molex splitter (connected to an AX850 Molex cable) in the third spot, but i don't know if this is safe.  Should I just get a new modular PSU?

 

 

Many thanks.

Edited August 13, 2021 by TigerWoody76

[LeDoyen]

for a 3070Ti, using one 8 pin + a pigtail should be enough. The founders is rated at 290W, which 2 cables can supply with ease.

That said if you have cash to spare, your PSU is 10 years old, so there's no telling what its ripple filtering is like with aging capacitors. Now that you're going to increase power draw even more, it may be time to think about getting a replacement.

[FlawlessSoul]

7 hours ago, TigerWoody76 said:

Does this go into the vacant 4 pin connection (ATX-12v-2)  next to the 8 pin ATX 12v connection (ATX-12v-1)?

This is correct. On the PSU side, the ports are keyed so you can't accidentally plug something into the wrong place. Likewise, the other end is keyed for the component it's attached to.

The 4+4 is for your motherboards supplemental power and, as you've correctly divined, connects to the additional 4 pin header next to the already-connected 8 pin. It's not required for normal operation, and attaching it won't cause any issues.

[TigerWoody76]

18 hours ago, LeDoyen said:

for a 3070Ti, using one 8 pin + a pigtail should be enough. The founders is rated at 290W, which 2 cables can supply with ease.

That said if you have cash to spare, your PSU is 10 years old, so there's no telling what its ripple filtering is like with aging capacitors. Now that you're going to increase power draw even more, it may be time to think about getting a replacement.

Thanks for all your answers, the Ax850 was actually never used, my friend just had it for a build but never used it and had it in the closet, so hopefully ill be ok for a few years?  for some reason my new 3070ti would not power on with only two 6+2’s plugged in.  I had an AX850 12pin to 8 pin CPU 12v ATX plugged in powering the CPU.   come to find out, after looking everything over, the 12 pins on this only had 8 pins and 4 were blank….so i swapped this out, put another AX850 12pin to PCIe in my third GPU slot and used a new AX850 8 pin to 8pin in the vacant 8 pin spot on the back of my PSU to power the CPU.  All is good

[TigerWoody76]

[LeDoyen]

2 hours ago, TigerWoody76 said:

Thanks for all your answers, the Ax850 was actually never used, my friend just had it for a build but never used it and had it in the closet, so hopefully ill be ok for a few years?  for some reason my new 3070ti would not power on with only two 6+2’s plugged in.  I had an AX850 12pin to 8 pin CPU 12v ATX plugged in powering the CPU.   come to find out, after looking everything over, the 12 pins on this only had 8 pins and 4 were blank….so i swapped this out, put another AX850 12pin to PCIe in my third GPU slot and used a new AX850 8 pin to 8pin in the vacant 8 pin spot on the back of my PSU to power the CPU.  All is good

Regarding old unused PSUs, i'd reference you to this post from Jonnyguru

Your build looks like a dust trap to be honest... 

 

There's a big fluff just there ! lol

[TigerWoody76]

Good to know, thanks.....time to go shopping again

[jonnyguru]

21 hours ago, TigerWoody76 said:

Thanks for all your answers, the Ax850 was actually never used, my friend just had it for a build but never used it and had it in the closet, so hopefully ill be ok for a few years?  for some reason my new 3070ti would not power on with only two 6+2’s plugged in.  I had an AX850 12pin to 8 pin CPU 12v ATX plugged in powering the CPU.   come to find out, after looking everything over, the 12 pins on this only had 8 pins and 4 were blank….so i swapped this out, put another AX850 12pin to PCIe in my third GPU slot and used a new AX850 8 pin to 8pin in the vacant 8 pin spot on the back of my PSU to power the CPU.  All is good

That's a REALLY OLD PSU.  Are you sure you want to use it?

 

But as stated earlier:  When you have THREE 8-pin connectors, you can use one pig tail on two of those connectors.  The GPU doesn't consume THAT MUCH power.