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ROG STRIX-GTX1080-A8G-GAMING Only Running At Half Its Rated Link Speed

MikeS3000
Level 7
I built my system in January 2017. I have the graphics card mentioned in the title and I just noticed the other day that my card only runs at x8 link speed in my Asus Maximus IX Hero motherboard in the top x16/x8 PCIe slot. I re-seated the card a few times as well. I tried removing all other PCIe devices (just a wifi card) as well as any M.2 storage devices and no change. What's even stranger is that when I move the card to the lower PCIe x8 slot I only run at x4 speed in the BIOS! Is there something wrong with my graphics card or motherboard to essentially run the card at half the rated speed in each PCIe port?
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12 REPLIES 12

Marcello_S
Level 7
Have you tried to run GPU-Z? You should be able to check at BUS Interface box the rated BUS speed which is actually been used by the graphic card. As far as I know modern GPUs use power saving feature like halfing the bandwidth or lower own BUS interface speed.
Did you compare your graphic card score or benchmarks results to others that have the same GPU of yours?

MikeS3000
Level 7
Yeah, GPU-Z says it's rated for PCIe 3.0 x16 but it only runs at x8. I tried ASUS support and they don't have an answer. It's either a faulty graphics card or motherboard. I need to pull the card and put it in a new B350 Ryzen motherboard that I built as a simple work computer. I just haven't had the time. The benchmark scores are fine and I know that this card won't even saturate the x8 BUS but if the board is faulty and I wan't to upgrade then x16 really will be required for future cards to get full performance. I don't really want to RMA the card if it is faulty because it overclocks pretty well. If it is the motherboard that is faulty I will probably RMA that.

MikeS3000 wrote:
Yeah, GPU-Z says it's rated for PCIe 3.0 x16 but it only runs at x8. I tried ASUS support and they don't have an answer. It's either a faulty graphics card or motherboard. I need to pull the card and put it in a new B350 Ryzen motherboard that I built as a simple work computer. I just haven't had the time. The benchmark scores are fine and I know that this card won't even saturate the x8 BUS but if the board is faulty and I wan't to upgrade then x16 really will be required for future cards to get full performance. I don't really want to RMA the card if it is faulty because it overclocks pretty well. If it is the motherboard that is faulty I will probably RMA that.


Could you please upload an image of your GPU-Z stats?

I'll show you mine:
70697

You should check Bus Interface box and see the actual Bus speed of your GPU, and if you click on the "?" button, it'll starts a render test to show effective capability of the Bus Interface speed of your graphic card.

By the way I highly doubt that you will use this motherboard with GPUs that will saturate the Bus Interface. Most likely you'll have a new motherboard by the time to upgrade GPU x16 will come. So far only Titan Volta manage to saturate x8 Bus Interface, and even then by not much actually.
Here's the video about: x8 vs x16 limit

MikeS3000
Level 7
I'm famililiar w/ GPU-Z. I don't have a screenshot but I'll tell you it's the same as your on the BUS interface but it always reads "PCIe x16 @ x8 3.0". No change at idle or under load because I don't have any power saving features enabled that I know of. The Maximus IX Hero reads x8 native always in the BIOS when you look at the GPU post information. I have forced Gen3 as well from auto and no change. Once again the x8 PCIe slot cuts the bandwidth to fulltime x4 3.0 when I tried that slot. I"ll probably just live with it since I'm not planning on an SLI setup and like you said I'm not saturating even the x8 3.0 BUS with my GTX1080.

MikeS3000 wrote:
I'm famililiar w/ GPU-Z. I don't have a screenshot but I'll tell you it's the same as your on the BUS interface but it always reads "PCIe x16 @ x8 3.0". No change at idle or under load because I don't have any power saving features enabled that I know of. The Maximus IX Hero reads x8 native always in the BIOS when you look at the GPU post information. I have forced Gen3 as well from auto and no change. Once again the x8 PCIe slot cuts the bandwidth to fulltime x4 3.0 when I tried that slot. I"ll probably just live with it since I'm not planning on an SLI setup and like you said I'm not saturating even the x8 3.0 BUS with my GTX1080.


Perhaps at this point we should ask someone who has the same your system (at least motherboard and GPU) and see if he reports the same.
So if I understood correctly while my GPU is rated at:
- PCIe x16 3.0 @ x16 1.1
Your is rated at:
- PCIe x16 3.0 @ x8 3.0
Am I right?
Could you please open GPU-z and click the "?" button next to the Bus Interface box? Once you click it start render test and the Bus Interface box should display a different speed.

I.e. after I click the "?" button my bus speed change from "PCIe x16 3.0 @ x16 1.1" to "PCIe x16 3.0 @ x16 3.0".

MikeS3000
Level 7
No change when I run a render test. And you may be a bit confused by the GPU-Z numbers. The first number is the maximum that the card "supports" and the 2nd number is what it is currently running at. I support PCIe x16 but can only max out at x8 3.0. You have power saving enabled so the BUS increases throughput on-demand.

MikeS3000 wrote:
No change when I run a render test. And you may be a bit confused by the GPU-Z numbers. The first number is the maximum that the card "supports" and the 2nd number is what it is currently running at. I support PCIe x16 but can only max out at x8 3.0. You have power saving enabled so the BUS increases throughput on-demand.


Indeed it was just what I was saying. I prefere write down all informations as possible to make thing clearer.
So after starting the render test your Bus Interface speed indicator simply remained as it was. My power saving feature slows the Bus Interface speed down from 3.0 to 1.1 but it still rated at x16, rather than your which is stable x8 @3.0.
This guys has the same "issue" check it out: 1080 Ti @ x8 3.0.

Chino
Level 15
Inspect the PCIe slot and make sure your GPU is inserted properly. Many times the GPU looks like its all the way in.

Chino wrote:
Inspect the PCIe slot and make sure your GPU is inserted properly. Many times the GPU looks like its all the way in.


I guess I don't know how to verify that other than visually seeing the tab click into place. I've inserted and re-inserted a few times, included in the other PCIe x8 slot and each time the BUS speed is cut in half of what the slot is rated. I do feel as if there is a problem with the Maximus IX Hero board. Look at the heatsink to the right of the board. My graphics card basically bottoms out on it so I guess it's possible that is causing interference with completely seating the card. However, if the card really were not seated all the way, how would it even produce an image? I'm sure that other major issues would occur more than just a decreased BUS speed.

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