help Daisy Chain 7900xtx

[Boone2112]

Hi all! So I've been asking around Reddit and the general consensus is for the most part it will be fine but I'm hoping I can get a more expert or at least more educated answer before I try to daisy chain my 7900xtx.

 

I made the mistake of ordering the NZXT C1200 watt Gold power supply assuming it had 3 PCIE like the c1000 watt version.

 

To my disappointment these ass hats decided it was a great idea to cut costs at consumers expense and give 2 PCIE, 2 CPU and 1 12vpwr cable instead of just including all cables one might need for the 280+$ price tag of the PSU (250€)

 

My options are to either use one cable for two power connections and a second cable for the last power connection or buy a new power supply. Why you might ask?! Because NZXT changed OEMs for the c1200 and that OEM hasn't disclosed the PCIE pin outs to cable mod and NZXT is refusing to do anything about it, their response to my support ticket was "go fuck yourself buy the cable from cable mod.com" in their own "professional" manner

 

I'm pretty desperate at this point and I'll be very grateful to hear what you guys have to say about it.

 

Thanks very much in advance 

[jaslion]

3 minutes ago, Boone2112 said:

My options are to either use one cable for two power connections and a second cable for the last power connection or buy a new power supply.

Just daisy chain its fine. Also dont buy a new psu just get some extra cables for it if you are really that bothered by it

[emosun]

3 minutes ago, Boone2112 said:

My options are to either use one cable for two power connections and a second cable for the last power connection

yeah thats how you connect it
 

[Boone2112]

1 minute ago, jaslion said:

Just daisy chain its fine. Also dont buy a new psu just get some extra cables for it if you are really that bothered by it

Unfortunately cable mod doesn't stock the cable due to them not knowing the PCIE pin out because the new OEM of this module apparently hasn't disclosed it in the year or so it's been released 

[jaslion]

52 minutes ago, Boone2112 said:

Unfortunately cable mod doesn't stock the cable due to them not knowing the PCIE pin out because the new OEM of this module apparently hasn't disclosed it in the year or so it's been released 

Ok so just daisy chain it. It's fine. The only time that was an issue was with the first release of rtx 3000 cards and rx6000 cards due to the psu's not being made with those high transient spikes in mind. Which was later resolved with updates and newer more robust psu designs

[Boone2112]

3 hours ago, emosun said:

yeah thats how you connect it
 

No-one recommends doing this neither motherboard, PSU or GPU vendors, but one nice user on Reddit explain since the 3090 power spikes PSUs have had a way more robust design for their power delivery and power rails and that daisy chaining it would be fine and not cause any damage even after benching it, but I'm still somewhat worried about it since I spent 3 years saving for a flagship PC, it's my 3rd personal custom build, but have built 5 for other clients 

[IkeaGnome]

5 hours ago, Boone2112 said:

To my disappointment these ass hats decided it was a great idea to cut costs at consumers expense and give 2 PCIE, 2 CPU and 1 12vpwr cable instead of just including all cables one might need for the 280+$ price tag of the PSU (250€)

They did give you more than enough. You've got 2 PCIE cables with a total of 4 connectors for the graphics card. Unless you have some weird 7900 xtx that takes 5 PCIE connectors?

[Boone2112]

2 hours ago, IkeaGnome said:

They did give you more than enough. You've got 2 PCIE cables with a total of 4 connectors for the graphics card. Unless you have some weird 7900 xtx that takes 5 PCIE connectors?

I have never daisy chained a GPU before and I'm just worried that it would not be enough.. so I'm coming to you guys and Reddit to ease my concern, it's just the Asus TUF 7900xtx with 3 connectors. Is this enough? Also thanks for taking the time to give your input.

 

I had been scouring the internet in search of just how much power these PCIE cables will hold in contrast to the wattage the card can pull but I've been coming up short for actual specific answers.. I just don't wanna risk ruining my card 

[IkeaGnome]

5 minutes ago, Boone2112 said:

Is this enough?

 

7 hours ago, jaslion said:

Just daisy chain its fine.

 

7 hours ago, emosun said:

yeah thats how you connect it

 

4 hours ago, Boone2112 said:

ut one nice user on Reddit explain since the 3090 power spikes PSUs have had a way more robust design for their power delivery and power rails and that daisy chaining it would be fine and not cause any damage even after benching it,

 

It still is enough. People get scared because the connector on the GPU is rated for 150W, but the actual wires are rated much higher. With 2 cables and a pigtail you're good for 525W. 150+150+150+75.

9 minutes ago, Boone2112 said:

I had been scouring the internet in search of just how much power these PCIE cables will hold in contrast to the wattage the card can pull but I've been coming up short for actual specific answers..

Even if your power supply uses 18 gauge wiring each wire is good for 10 amps. So 120W per wire. That's pushing it and you'd never ever see that much on a single wire. Each 8 pin has 3 wires that actually transfer power.

If the connector could handle it, you could run that gpu off 1 8 pin...

If it makes you feel better, my 4090 has 3 power cables going to the 8 pin adapter. And my 6800xt ran off 2 cables for 3 connectors just like you'd be running.

Spoiler

That chart is for spikes, so worst case scenario.

Spoiler

That's more like what you'd expect in games. 

In theory, the max you can draw with 2 pcie cables with 1 being pigtailed is 525W. 150W from cable 1, 300W from cable 2, and 75W from the PCIE slot. However, if you ignore the connectors as the cables seem to be part of your worry, the cables and pcie slot can handle 795W. 75W from PCIE slot, 360W from cable 1, 360W from cable 2. You would never see anywhere near that much though and if you get to that wattage you've got other problems. The PCIE cables aren't the things to worry about if you hit both of their max limits at the same time. 

[emosun]

5 hours ago, Boone2112 said:

but one nice user on Reddit explain since the 3090 power spikes

k are you using a 3090 or a 7900

[Boone2112]

1 hour ago, IkeaGnome said:

 

 

 

 

It still is enough. People get scared because the connector on the GPU is rated for 150W, but the actual wires are rated much higher. With 2 cables and a pigtail you're good for 525W. 150+150+150+75.

Even if your power supply uses 18 gauge wiring each wire is good for 10 amps. So 120W per wire. That's pushing it and you'd never ever see that much on a single wire. Each 8 pin has 3 wires that actually transfer power.

If the connector could handle it, you could run that gpu off 1 8 pin...

If it makes you feel better, my 4090 has 3 power cables going to the 8 pin adapter. And my 6800xt ran off 2 cables for 3 connectors just like you'd be running.

  Reveal hidden contents

That chart is for spikes, so worst case scenario.

  Reveal hidden contents

That's more like what you'd expect in games. 

In theory, the max you can draw with 2 pcie cables with 1 being pigtailed is 525W. 150W from cable 1, 300W from cable 2, and 75W from the PCIE slot. However, if you ignore the connectors as the cables seem to be part of your worry, the cables and pcie slot can handle 795W. 75W from PCIE slot, 360W from cable 1, 360W from cable 2. You would never see anywhere near that much though and if you get to that wattage you've got other problems. The PCIE cables aren't the things to worry about if you hit both of their max limits at the same time. 

This has definitely helped me understand it alot more and ease the concern thanks very much I'll give this an installation tomorrow!