Hello,
 
I have questions regarding how much wattage these cables can safely transfer from the PSU to GPU's. I understand that 6pin can safely give 75W and the 8pin can safely give 150W. I saw a resource that stated that good PSU's can safely (rated?) give up to 288W at the same time if both dual 6+2 pins are connected to one GPU. 
 
I'm under the assumption that a single PCIE dual 6+2 cable can safely support the power draw from a GPU if the MAXIMUM possible power draw is under 288W. There are a lot of modern cards now that have a steady 150-200W requirement (maybe 250W jump when just turning on first few seconds) that has two 8pin receivers (for example, RTX 3070). 

So I need to know what EVGA says what the max rated wattage the PSU can safely give to the cable if both 8pins were connected to one GPU.

It's 850W. My question is simple, no? I thought I overexplained what I'm looking for as I'm focused on the PCIE to dual 6+2 pins and nothing else.
 
If I plug both 6+2 pcie pins into the GPU how much can the PSU safely provide the GPU - what is the safety limit and how much wattage should not be exceeded on one PCIE dual 6+2 pins?

Is it 288W as per this diagram? Is it 300W becaues two 6+2 pins = 300W?
 
Is it 225W because the first 6+2 pin is the main connector which should be used as 150W, and the second should really be 75W max because these wires are really an extension of the first 6+2 and not on separate wires leading to the PSU connector?

As per my first post "So I need to know what EVGA says what the max rated wattage the PSU can safely give to the cable if both 8pins were connected to one GPU?" When I mean "both 8 pins" I mean the dual 6+2 pcie's.

Thank you.

Bob, I understand the Pcie slot on the mobo or even riser can provide 75W. We know that 8 pin is 150 and 6pin is 75. 
 
What is the max safe wattage one of these dual pcie's can provide? 
 
You know what, EVGA is telling me to power a <200W card with two different PCIE cables instead of one PCIE dual 6+2. Why the heck did I buy an EVGA video card, and EVGA PSU, and they provide a PCIE dual 6+2, and they tell me to use two different PCIE cables, and won't tell me how much wattage the single cable can provide to GPU's if both of them are plugged in. Why the heck do they even provide pcie dual 6+2 if they can't supply a mid level GPU with one of these cables? Apparently, 200W is "unsafe and/or unstable" for one of these cables. Looking for another option because it seems ridiculous. 
 
You said they can "handle more". No kidding, they can handle bursts above 150W but steady draw above that isn't advised? Sata can handle more than 54W but for how long before you fry the pins? I am asking what the safe amount of wattage a single pcie dual 6+2 can provide. I am under the assumption it's rated for 288-300W but an EVGA rep advised to use two different cables to power one 200W GPU. lol.
 
The link you provided has zero information regarding pcie dual 6+2 connectors. The calculator you provided is only a calculator and I don't feel it's sufficient to provide evidence of what the CABLE ITSELF can safely provide the GPU if both 6+2 pins are connected to one GPU.

Hope you can see my frustration on this matter. 

It's all right there..75W + 150W = 225W = The maximum PCI-SIG (industry-standard) rating..Windows has a calculator if you need it.
 
I suspect that if EVGA and other PSU manufacturers are gonna include PCIe 'Y' cables with their units, then they are rated for the load, plus more..Actual Terminal/Connector power-handling capability is in the chart.

LordSyrion
I would use individual cables regardless and not rely on a single Y cable to power to multiple connections on any modern GPU.

Why? Some modern GPUs require less than 200W ongoing but have two 8pins to handle any OC, starting it up etc. If the Y cables can handle 225W safely ongoing as evga stated and the motherboard can offer 20-40W ongoing on these lower power yet modern GPUs, then why would you still use two different ports on the PSU?
 
I can see you have a rtx 3080 so you may be biased in what you have as it's rated for 320 watt so fair to use two vga ports. But if you had a 3070 do you really need to use two ports when its max rating is ~220W, I don't think so.

wmmills

blacknblue

LordSyrion
I would use individual cables regardless and not rely on a single Y cable to power to multiple connections on any modern GPU.

Why? Some modern GPUs require less than 200W ongoing but have two 8pins to handle any OC, starting it up etc. If the Y cables can handle 225W safely ongoing as evga stated and the motherboard can offer 20-40W ongoing on these lower power yet modern GPUs, then why would you still use two different ports on the PSU?
 
I can see you have a rtx 3080 so you may be biased in what you have as it's rated for 320 watt so fair to use two vga ports. But if you had a 3070 do you really need to use two ports when its max rating is ~220W, I don't think so.

The AWG, or wire gauge, on the Y cable youve mentioned can only safely handle 220 watts, that is the reason. Prolonged high current, especially higher than that which they are designed for, can melt the vinyl sheath, the plug and inadvertently connect wires/pins etc... Using two separate wires in each pci-e will guarantee you less heat resistance to the gpu, better electrical delivery and stability and headroom if actually needed. Just cause you CAN do something doesnt mean you should. I hope that helps clear it up for you.

RTX 3090's have almost double the peak gaming performance as the rtx 3070. If it's unsafe and dangerous as some people say to power one rtx 3070 with one dual 8pcie, then it is almost as unsafe to power an rtx 3090 with two ports from the PSU, as per its standard requirement for many of the models lol... The rtx 3070 will demand ~20W from the mobo and the remaining ~180 from the pcie at max gaming performance. If it's safe to use <220W from these 2 dual pcie's, and each 8pin offers the card ~90W each, I don't see how this is an example of "just because you can you shouldn't" scenario, especially when people don't usually fully OC their cards to those limits. I can see your comments applying to people trying to connect a 1080 Ti or 2060 with one dual 8pin as those push ~275W+ and the overheating and inefficiencies would be more noticeable sooner or later. I'm running 3070's at ~140W steady and 20W is coming from the mobo. 120W from the dual 8pins seems reasonably safe and I don't think I should experience overheating or melting parts or inefficiencies (<1% max?). Thanks for input.