GPU Voltage Question- PCIe 12v Rail Voltage Specifically

[Dave1001]

when playing games, generally this happens in Destiny 2, obviously the GPU voltage may increase which will cause the PCIe 12v Rail voltage to sag; however, I want to know if my line is sagging too much, or if there's any kind of "threshold" that it should not sag past. obviously there's the ATX spec limits but other than that, is there any?

essentially, whenever my Power Draw hits around 98-100+ watts, the GPU Voltage will go to 1.04-1.08v (normally it operates at 0.7-0.9v under load). when this happens, the PCIe 12v Rail will sag down to 11.8v, specifically usually 11.87-11.89v; this may be for 2 seconds, or it might last for 5-6 before rising back to normal

my usual PCIe Rail Voltage is 12.05v and I've heard conflicting reports about "how far" the voltage should drop under load; I've heard people say it should never fall past 11.89v, I've heard people say it should never drop beyond 0.2v of your normal voltage, etc.


just before, I dropped down to 11.856v on the PCIe 12v Rail which is pretty close to that "0.2v threshold" I heard about. I know it's well within ATX spec and everything but should I be concerned about these drops in the PCIe 12v line when the GPU Voltage spikes?


my GPU is a Gigabyte RTX 3070 and my PSU is a Phanteks Revolt Pro 1000w, so it's more than capable of powering the card and my other components. Destiny 2 is really the only game I play that pulls more than 100 watts at certain times, so as of right now this is the only game that causes this level of sagging (outside benchmarks of course)

 

[Martin]

It's pretty common for the +12V rail to drop slightly under higher load. 11.85 should be still OK.

 

[Dave1001]

It's pretty common for the +12V rail to drop slightly under higher load. 11.85 should be still OK.

even at 100 watts? the max of the 3070, I believe is 220-230w, so for the PCIe 12v Input Voltage to droop from 12.05v to this 11.85-11.89v range after reaching 100 watts is definitely okay? typically, I've never observed the game to push the GPU past 130 watts


under a benchmark with highest settings possible the PCIe 12v Input Voltage comes out between 11.80-11.85; a fair droop but it's not really what occurs under usual gaming load.

I don't play Destiny 2 on very high graphics, pretty "Medium" across the board with a lot of 'useless' settings put to "Low" or "Off", so I'm sort of just concerned at the droop I experience after reaching 100 watts and exceeding 1v on the GPU

 

[LeDoyen]

the PCI spec for a good voltage is like down to 11.4V (5%) so you have a pretty hefty margin as you already know.
Of course you should never go down that low. People have this kind of voltages when using cable extensions, but when using direct connexion to the PSU there is never any problem.
11.8 is totally fine.
That said, if you use a single pigtail cable (2x8 pin on a single cable) you will see more Vdroop than if using two discrete cables. These cables should be avoided whenever possible.

 

[Dave1001]

the PCI spec for a good voltage is like down to 11.4V (5%) so you have a pretty hefty margin as you already know.
Of course you should never go down that low. People have this kind of voltages when using cable extensions, but when using direct connexion to the PSU there is never any problem.
11.8 is totally fine.
That said, if you use a single pigtail cable (2x8 pin on a single cable) you will see more Vdroop than if using two discrete cables. These cables should be avoided whenever possible.

admittedly, I didn't assemble this PC myself and it's in a less-than-convenient location for me to just take a peep at the GPU or PSU (it's in a little cove underneath the desk; plenty of airflow and space for it, but makes it impossible to look through the side panel without pulling it out)


so I'm not sure what cables are used, most I know is that there's values for an 8-pin Connector and a 6-pin Connector on HWInfo, alongside the PCIe value but I doubt that says much


I selected my PC parts on PC Case Gear and they assembled it and shipped it; that was in February this year. PCCG is pretty reputable so I imagine they would hook up the cables properly without "outdated" or poor methods like the pigtail cable

pretty sure the Phanteks Revolt Pro 1000w doesn't come with cables as well, on its own at least. which is always annoying. I don't typically Vdroop to 11.8v unless benchmarking or playing Destiny though, so I probably don't have that kind of cabling?

it droops to 11.8v (11.88-11.89 specifically) once it breaches 100-110w on Power Draw, but not many games reach that 100w threshold for me tbh

 

[LeDoyen]

I don't think the phanteks branded cables are pigtails, but it's worth looking when you can.
the 3070 (non TI) is 220W so, one 8 pin and one 6 pin. if you see two separate cables going to the GPU, then that's all there is to see and you can't really change the voltage drop, which again, is totally fine.

 

[Dave1001]

I have this image from when I first got the PC but I’m not sure if this shows the “cables going into the GPU” that you mention (super unknowledgeable about cables and connections)

PSU is in that black area at the bottom, which I think is a shroud; Phanteks Eclipse p360a case