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PCI-E runs at x8 instead of x16

_fess
Level 8
Hello,

I've recently updated BIOS to 0802 and GPU seems to have started running at "native x8 link speed." It used to always run PCI-E 3.0 @ x16, but now BIOS, GPU-Z and CPU-Z all show that it runs PCI-E 3.0 @ x8. Running GPU-Z render test or UNIGINE benchmarks doesn't help. It still shows PCI 3.0 @ x8. Clearing CMOS, reseating vid card didn't help. Running BIOS at optimized defaults didn't help. I'm running out of options here. Do you think I "broke" the mobo or vid card somehow or is it the BIOS issue. I hope it's the latter one. PC is only a month old and I had no issues with it until the recent BIOS update from 0505 to 0802. Here are my specs:

BIOS: 0802
OC'ed? No.
Motherboard: Asus ROG MAXIMUS X HERO (WI-FI AC)
CPU: Intel Core i7-8700K
AIO: Corsair H100i v2
RAM: Corsair Vengeance LPX 32GB (2 x 16GB) DDR4-3200
SSD: Samsung 850 EVO-Series 500GB 2.5"
NVMe (Boot): Samsung 960 PRO 512GB M.2-2280
NVMe (Games): Samsung 960 EVO 1TB M.2-2280
Graphics Card: Asus GeForce GTX 1080 Ti 11GB STRIX GAMING
PSU: EVGA SuperNOVA P2 850W

Thank you for your help!
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52 REPLIES 52

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Question... Just noticed my Gigabyte GTX 1070 G1 PCIe_x16 adapter is only running at x4 on PCIex16_1 slot One! I have only one drive installed which is a PCIe_x4 NVMe 3.0 stick in slot M.2_1. According to everything I've read, including the manual, M.2_1 should NOT affect PCIex16_1. Since it's my boot drive, I can't (not do I want to!) pull the NVMe drive to see if the video adapter jumps to it's default x16 mode. Both the BIOS and GPU-Z report the current x4 bandwidth. BIOS doesn't even list the PCIex16_1 to adjust settings. The other 2 slots are present, w/optional settings. It's an 8/16 core Ryzen 7 2700x so I can't see the CPU lanes as a limiting factor?

I found an "Intel i5" post that suggested it could be the sound circuitry built into the GTX adapter "and" Motherboard hogging up lanes, but found no help on the Ryzen 7. This is a new build and my first Ryzen so I'm learning as I go. Any thoughts?


AMD Ryzen 7 2700x
Asus ROG STRIX x470-F
16gb G.Skill TridentZ RGB (2x8)
Gigabyte 1070 GTX G1 Gaming 8gb
Intel 660p M.2 nVME 3.0 1024GB
Corsair tx850w PSU

https://www.newegg.com/intel-660p-se...82E16820167462

https://www.gigabyte.com/us/Graphics...-8GD-rev-10#kf

Silent Scone wrote:
Firstly can you confirm if the GPU is in PCIe x16/x8_1 (the top 16x length slot on the board)?

Is there anything in If PCIe_x8_2? If this slot is occupied, PCIe x16/x8_1will revert to 8x mode.


Confirmed, the GPU is in the top PCIe x16/x8_1. There's nothing in PCIe_x8_2 and I've never used this slot to date.

Silent Scone@ASUS wrote:
Firstly can you confirm if the GPU is in PCIe x16/x8_1 (the top 16x length slot on the board)?

Is there anything in If PCIe_x8_2? If this slot is occupied, PCIe x16/x8_1will revert to 8x mode.


I have just the Video Card that is using the PCIe slot, utilizing the riser cable as the Noctua Cooler is so large it will not allow the video card to be inserted directly into the slot itself.

Menthol
Level 14
Is the card fully seated, is your case not allowing the card to seat fully (test system outside of case similar to how the store tested)
what power supply? is it single rail? multi rail? if multi rail make sure there is nothing else that uses the same voltage rail as the video card

I have no issue on my X Hero, any bios with 1080 in slot 1 &X16

Menthol wrote:
Is the card fully seated, is your case not allowing the card to seat fully (test system outside of case similar to how the store tested)
what power supply? is it single rail? multi rail? if multi rail make sure there is nothing else that uses the same voltage rail as the video card

I have no issue on my X Hero, any bios with 1080 in slot 1 &X16


Yeah, i might have to try that again. I have EVGA 850 P2 power supply.

I had a 1080 before and had no issues with it at all. It's the Ti that's giving me grief not just on Maximus X Hero, but on the 4-year old z87-k platform as well.

SOLVED! After all said and done, turns out the issue was with the motherboard itself. After exchanging the mobo for an idnetical one, the problem went away and GPU runs at pci-e 3.0 x 16 with everything plugged in, including two M.2 drives.

Thank you everyone for your help.

I have still the same problem. Tested several GPUs and all shows x8 on this board (All are working at x16 with an GA-Z97x-Gaming 7 from Gigabyte). CPU is an Intel Core i7 7820x. I have updated the BIOS from 0503 to the (at this time) actual version 0802. I have then sent the board to ASUS and they send it back after a month without solving my problem. I have also reassembled my components but the GPU is still at x8. They didn't replaced the board but updated it to version 1004. They even took the original box away and all the additional equipment was stuffed in the same package as the mainboard when it arrived here. That was unexpected and I still want the original box back. ASUS didn't answered my questions since then, taking the original box and just sending my board back without any explanation.

Thanks for your help.

F-ZERO wrote:
I have still the same problem. Tested several GPUs and all shows x8 on this board (All are working at x16 with an GA-Z97x-Gaming 7 from Gigabyte). CPU is an Intel Core i7 7820x. I have updated the BIOS from 0503 to the (at this time) actual version 0802. I have then sent the board to ASUS and they send it back after a month without solving my problem. I have also reassembled my components but the GPU is still at x8. They didn't replaced the board but updated it to version 1004. They even took the original box away and all the additional equipment was stuffed in the same package as the mainboard when it arrived here. That was unexpected and I still want the original box back. ASUS didn't answered my questions since then, taking the original box and just sending my board back without any explanation.

Thanks for your help.


Hello
Can you please send me a PM with any of the following details that you do have available?

Product S/N:
Case ID#:
RMA#:

Also please pass me your contact details:
Full name:
Phone#:
Email:

I'll pass your case to related personnel and department for further investigation
Thank you

@f-Zero

Any hints, why you don't fill out an Support Formular or call Asus Germany, while you post here in a non german Forum?

Please call our line or fill out on our page the Support Formular. If You have this RMA Number: RMA#: 352944022 This ist not an Asus RMA number.

Give us also the hint, to which mail addy you have written to our rma. Maybe You have send in your device over your dealer and not over us.

The right rma address is: op_rma@asus.com