PCI-E runs at x8 instead of x16

[_fess]

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!

[paulmarc]

Granted, it's a different motherboard, but nearly the same family:

NeoandGeo wrote:
try reseating the GPU.

This made it work for me...

[bass_junkie_xl]

had this same pci x 8 x issue on my asus rog x hero z 370 it didnt do it when i first got it but then the bios under gpu post didnt even show the gpu was installed and inside windows only gave my 8x under load ... resetting didnt do anything .

then i thought maybee its the pcix riser cable i am using on my vertical 1080 ti in my thermal take view 71 glass case is acting up .

replaced riser cable for the vertical gpu and no issue now

[schweigert]

Currently having the same problem with an Asus Crosshair VII and RX480 - plugging the card directly into the board (or using an extension cable) still only getting 8x - as the only pcie card pugged in (into the 16x/8x slot)

as for throttling the card when not in use, it does go down to pcie 8x - 1.1 - but then jumps up to pcie 8x 3.0 when under load.

[dyni00]

i have this same problem ASUS Z370 GAMING-F and palit gtx 1080 gamerock premium ed.

i have x8 pcie on graphic card and no other devices on pcie. wtf? 😞 new bios on mobo (1406 ) but previous (1002 ) not works at x16 too

[bojerka]

I had same problem with ASUS Z87-DELUXE after deliding CPU (4790K). My GPU then running only on x8. Any GPU run on that mobo only x8.
I checked CPU socket if I damaged some pins but all looks OK. I check too PCIe slot but too looks clean and no damage.
Now this mobo with this CPU have my friend (GTX 1080 installed some GIGABYTE) and too runnig only on x8. Idle or full load still x8.

[kens30]

Try cleaning the the gold contacts on your gpu with isopropyl alcohol and test again.
Sorry i just read that your problems started after you delided your cpu so it is most likely you might have damaged some traces.

[frackzz]

Same problem on my Prime Z370-A and 1080TI.
This is clearly an ASUS problem and nothing to do with gold contacts.

[bojerka]

I cleaned CPU many times too I checked socket on board with magnifying glass and don't see any damage. Still problem persist.

[dyni00]

still x8 - no other pci-e devices, no m.2, onlu PALIT gtx1080 stillx8 but my friend not updated UEFI/BIOS (before spectre bug) and have x16!!!
I wrote to the support but ordered to send the mainboard to the service.
not possible for me. send me better mobo then ill send back to you this crap.

my suggest update UEFI/BIOS or not write to box SUPPORTED x16 PCIE

[bojerka]

so do you fix this problem? I updating BIOS too but I can't say on 100% if GPU drop on x8 after delid or after BIOS update. I don't remember.