30 series and PSU

[Quantum]

i have two pcie cables, each is daisy chained. Each has two 6 pin and 2 pin connectors. Theoretically i can power up a graphics card with only 2 cables, should this be done with a 30 series or 6000 series? I think two 8 pins would be fine using both cables but some graphics cards have three 8 pins.

[Bad 💀 Motha]

It doesn't matter; your PSU has 4x independent 6+2 pinned connections.
As long as its a decent model, gold certified or better PSU of approx 750W then you should be fine.

[r.linder]

It doesn't matter if it's daisy chained. Some people claim that using daisy chained PCI-e power cables is less stable but it's just a myth. I've tried both and it makes no difference.

You can use all connectors on one cable and the third set on the other cable just fine with the new GPUs. The determining factor in how stable it'll run is determined by the quality of the unit itself, not the cables you're using unless the cables themselves are faulty. The only time I had issues with cables being at fault was because of a faulty CableMod extension.

Due to power spiking, I recommend at least a 750W Gold rated PSU from EVGA, Corsair, SeaSonic, or be quiet!, as running the bare minimum of a lower quality unit could result in the PSU being overwhelmed and shutting off.

EDIT: Also bear in mind that Zen2 starts to suffer from diminishing returns going above a 3070 in comparison to competing CPUs from AMD itself (i.e. Zen3) and Intel due to a CPU bottleneck in many titles that are more demanding on the CPU. It's because Zen2 just can't reach and sustain boost clocks or overclocks as high as other CPUs (nor is it safe for them to run such clocks) so I really wouldn't recommend getting anything better than the 3070, save that for when you plan on upgrading your CPU later on. Given your current GPU, even that will be an astronomical change anyway.

[Bad 💀 Motha]

Can't go wrong with a Corsair HX750, or better

[CravenCoyote]

Though either would work, some PSU manufacturers (such as SeaSonic) do recommend that you don't daisy chain if it can be avoided

[Quantum]

Ursprünglich geschrieben von Angelwolf:

Though either would work, some PSU manufacturers (such as SeaSonic) do recommend that you don't daisy chain if it can be avoided

Thanks for all the replies, can you tell me why that is? Does daisy chaining lose voltage?

[CravenCoyote]

Ursprünglich geschrieben von Quantum:

Ursprünglich geschrieben von Angelwolf:

Though either would work, some PSU manufacturers (such as SeaSonic) do recommend that you don't daisy chain if it can be avoided

Thanks for all the replies, can you tell me why that is? Does daisy chaining lose voltage?

There are reports that when daisy chaining, cards can try to pull more power than what the equipment is rated for, so it is seen as safer to use separate cables per socket where possible

[Andrius227]

With most gpus a single cable is ok, i think. But i recently got an rtx 3090 and that thing can draw like 400 watts. Pulling that much power through a single cable would probably melt the cable and start a fire.

[Bad 💀 Motha]

I would stick to no more then a 3080 that has 2x 8pin connections if you can help it.

[Talby]

Ursprünglich geschrieben von Quantum:

...Thanks for all the replies, can you tell me why that is? Does daisy chaining lose voltage?

The connector itself introduces a bit of resistance, just like the wire itself - good read here[www.interpower.com] - a tight connection minimizes the connector resistance just like a shorter length of wire has less resistance than a longer one.

IMHO a single extension of good quality is fine, and try not to have your power supply across the room where you would need more than 1!

[r.linder]

The problem is, they usually only ever include 2 cables. So for GPUs using 3 connectors, you can't avoid it unless you have another cable on hand.

[Monk]

My 3090's,wont even power up without all 3 pins in, you get a, warning at boot.

If it's a power hungry top end card, you can get slightly better performance out of individual cables over daisy chain, jayz2cents covered it some time ago.

I just run full cables for each anyway, if you don't have enough connections for thst, it's probably a good indicator that your psu isn't upto the job.

[Bad 💀 Motha]

You could buy a higher end PSU that actually has 4x separate PCIE GPU cables.
Then to eliminate the funky looking daisy-chained connectors; buy proper replacements via CableMod where each PCIE GPU cable will only have 1 connector for each cable. Ensure that anything you buy like that, such as CableMod, is specific to your model of PSU. As not all modular PSU are wired the same within the modular plugs on the PSU-side.

[Quantum]

Ursprünglich geschrieben von Bad 💀 Motha:

You could buy a higher end PSU that actually has 4x separate PCIE GPU cables.
Then to eliminate the funky looking daisy-chained connectors; buy proper replacements via CableMod where each PCIE GPU cable will only have 1 connector for each cable. Ensure that anything you buy like that, such as CableMod, is specific to your model of PSU. As not all modular PSU are wired the same within the modular plugs on the PSU-side.

Alright, what PSU would you recommend besides a Corsair HX750? I currently have CX750M so that will have to do for now.

[Bad 💀 Motha]

Again though you should be fine.
As it's not a good idea to run a 3090 off that PSU.
And most 3080 will not have 3x gpu power connectors.

[xSOSxHawkens]

I guess I will be the outlier here...

Yes, it does make a difference. If you have 8 physical lines of copper, rated for X amount of current ideally, and Y amount under max load, and you choose to push the amount of 2x8pin connections via daisy chain, even if it is still in spec it *is* likely to cause stability issues in many cases.

It only takes a currsory search on google to find not one but multiple cases of support for both AMD and Nvidia, as well as PSU makers, all three stating the same thing.

Daisy chained PCIe *can* work, and ideally *will* work, without issue. But, given the option, you are *always* better off running a dedicated line per input to the card.

If you have the option do what the PSU makers, AMD, and Nvidia all three have espoused more than once over the years, and run the card with cables per input if you can. You wont be harming anything by daisy chaining, and you might even be perfectly fine, but its just better practice not to when you dont have to. Best case you will be pushing 12-16 leads worth of power down a 6-8 lead cable, even if that works forever its not the best way to do it.