GPU power pin connectors

[Newtype0085]

So I was looking at getting a new GPU pretty soon and I was wondering if anyone knows a formula to estimate how much power the maximum draw a GPU requires based on the pin connection layout.  As an example, if there is a single 8-pin connection vs a single 6-pin or a 6-pin plus an 8-pin.  This is not taking into account the 75 watts drawn from the PCI-E slot. In other words, a ballpark figure or the power requirement for a card with a single 6-pin, sinlge 8-pin and an 6 and 8-pin combination. I know my PSU probably won't be able to power a card with two 8-pin connectors, but I am looking at several Radeon cards that have a 6-pin and an 8-pin.  Most retailers state a minimum PSU wattage requirement, but I know these figures are inflated to take into account other cards, devices, and peripherals of the setup. 

[skimmilk5]

GPU power draw can't be determined by the connector. Some cards can draw 90w from a 6-pin connector, while others can draw upwards of 120w from that same connector. You'll have to check the individual card manufacturer's website. (Keep in mind that XFX's implementation of a certain card will differ from Asus's implementation of that same card, so you'll have to check all the cards you're looking at). Look at the raw TDP, which is generally a good representation of the amount of power taken (not the definitive number).

[DocSwag]

There's no good way to estimate it based on pin connectors. For example, a 1070 has an 8 pin, which combined with the pcie connector gives 225 watts, but in reality the power draw is more like 150 watts. On the other hand, a 295x2 has two 8 pins which added with the pcie slot gives 375 watts but in reality the power draw is more like 500-550 watts. The best you can do to estimate is just look at the tdp. I know the tdp isn't the same thing as the power draw but in generally it's pretty similar. If you want something more accurate just look for reviews by people like tom's hardware who measure the exact power draw of a card.

[Mira Yurizaki]

At best you can only estimate the minimum power draw it has based on what connectors the video card requires. You cannot estimate how much it'll actually use. However both AMD and NVIDIA put down the power spec on their website. But this is only for the stock version of the card. Board manufacturers will often sell overclocked versions that require more power.

 

If you really want to know what the maximum power delivery for each connector is though:

• PCIe slot: 75W
• 6-pin connector: 75W
• 8-pin connector: 150W

However this does not mean a card with a 6 and 8  pin connector will draw 300W. It may draw up to 200W. But you can guess it will chew up at least 150W (from the PCIe slot and 6-pin connector).

[Newtype0085]

Thanks for the replies,  This is a frustrating topic for me personally due to what I pointed out in the OP that the MSR givien by manufacturers are always seriously inflated due to having to cover a whole spectrum of other devices that may possibly be in a build.

4 minutes ago, DocSwag said:

There's no good way to estimate it based on pin connectors. For example, a 1070 has an 8 pin, which combined with the pcie connector gives 225 watts, but in reality the power draw is more like 150 watts. On the other hand, a 295x2 has two 8 pins which added with the pcie slot gives 375 watts but in reality the power draw is more like 500-550 watts.

These are two excellent examples of what I was talking about.  I know that cards are often rated outside of what they actually require.  This is why I was looking for a "ballpark" formula of how to determine the maximum TDP

 

5 minutes ago, M.Yurizaki said:

If you really want to know what the maximum power delivery for each connector is though:

• PCIe slot: 75W
• 6-pin connector: 75W
• 8-pin connector: 150W

However this does not mean a card with a 6 and 8  pin connector will draw 300W. It may draw up to 200W.

This is very helpful to know, I want to be certain of what the maximum possible  TDP parameters can be to make an estimate without having to dig through articles and review specs to rule out any GPU's that I know are definitely out of my power range.

 

Back @DocSwag, if the maximum TDP a slot and two 8 pin connectors can provide are 375, how is it even possible for an R9 295x2 to even draw that much power which exceeds the supply the connections can provide?

[Cela1]

58 minutes ago, M.Yurizaki said:

If you really want to know what the maximum power delivery for each connector is though:

• PCIe slot: 75W
• 6-pin connector: 75W
• 8-pin connector: 150W

*Stares at RX 480*

 

[Cela1]

58 minutes ago, M.Yurizaki said:

 

This is a dupe comment bro

[Mira Yurizaki]

First off, I want to clarify something since this is a pet peeve of mine. TDP is not power consumption. It's how much thermal energy is required for a cooler to dissipate in order for the GPU to run at the designed operating temperature given a nominal workload. Yes it's measured in watts, but in physics, anything that's energy over time, be it thermal, electrical, etc. is measured in watts. Because it's energy. And energy is all the same in the end.

 

Anyway.

 

The thing with power delivery is that the PCIe defines a maximum power delivery. However, all that means is to be compliant, you have to be able to supply up to that much safely. If your power delivery system is built with more beef, you can exceed the power delivery spec safely. This is why the RX 480 burns out some boards but not others. But again, there's no easy way to determine the maximum power a video can consume based on its connections alone.

 

As in my previous example, a video card that consumes 200W may use a 6-pin and 8-pin connector rather than say a single 8-pin because the headroom is 25W. Maybe you need to worry about power spikes, overclockers, etc. So you put on another 6-pin connector to give yourself another 75W of breathing room.

 

In any case you can only rely on two things: what the manufacturer says (NVIDIA and AMD both have typical board power consumption for the stock card listed on their website) and what reviewers say, if they do a power measurement test (Tom's Hardware is the only one I know that does an isolated test).

[Mohitb]

The pins hardly tell you anything. if you want a proper number, there are a number of power draw calculators online.