Just wanna make sure you put your mobo in 3.0 mode and not auto right? Many of us that use vertical GPU's have to do this on amd boards.

slayertx
Just wanna make sure you put your mobo in 3.0 mode and not auto right? Many of us that use vertical GPU's have to do this on amd boards.

It would be an Intel board though and I doubt any intel boards would have gen4 as an option.

OP
It could just be the riser cable tbh. Do you have a link to the cable?

jonkrmrDoes the 3080 work directly in the PCI-e x16 slot on the MB?

 
i haven't tried that yet, but i might remove the motherboard and try it because...
 

Johnny5srvI would just spend a few dollars on a more suitable case so you don't need to use the riser cable at all.  Then again I would have upgraded the rest of the system before upgrading from a 1080.

that did occur to me, but i thought the vertical mount would be cheaper.  it turns out that Microcenter has a selection of cases for $10 less than the vertical mount, so i might just return the vertical mount and get a case that can accommodate my parts.  they're not great cases, of course, but it'd just be temporary.
 
heh, the whole reason i'm getting this card before building a whole new box is pretty much just because Cyberpunk 2077 comes out before the next Intel gen (and the subsequent AMD comparisons).  i plan on a tasty new rig once the next CPU gen has settled down a bit.
 
all that aside, i still think it would be useful to have a software switch for PCIe 4.0 and 3.0.  there may be people with no option but to use a riser, unforeseen compatibility issues, or just the desire to do some troubleshooting or benchmarking.

hi Cool, thanks for responding - i forgot to mention that i did try resetting the CMOS, though i don't know if that restored automatic XMP.  i'll try disabling that if it doesn't work when directly connected to the mobo.
 
one odd thing is that switching my mobo to the PCI UEFI ROM option won't boot with this card, and i think won't boot with the 1080 either; i have to use "legacy".  that might just be a quirk with the P8P67 Pro (it's an old mobo and early-gen EFI), as GPU-Z correctly shows the UEFI flag for the 3080.

Q-LED indicators ?
 
https://www.asus.com/support/FAQ/1042678
 

Also I would suggest for You all PCIE 4.0 cables from https://linkup.one/ Im using them, had no problems at all.

update time: it works!  more or less.  first off, thanks for all the responses.
 
so, i think there were actually two issues that appeared nearly identical:

1. the card didn't like the riser cable
2. the card didn't like some BIOS/EFI setting

last night i returned the vertical GPU mount and picked up the cheapest ATX case they had: a Thermaltake V100 for US$50 ($20 less than the GPU bracket).  this is just temporary until my new build.
 
before loading everything up, i tested the mobo on the table with the GPU directly hooked up.  it did not POST!  on a hunch, i decided to clear the CMOS again and it booted.  now, i had tried clearing the CMOS before when using the PCIe extension cable and it did not work.  i restored my saved CMOS settings and it went back to failing.  so, both the cable and the CMOS settings were incompatible.
 
i had noticed that sometimes the POST beeps and mobo diagnostic LEDs would behave differently, so the two different failure causes may explain that.
 
so, now i'm back to the default CMOS settings plus XMP RAM (DDR3-2133) and a modest 500MHz overclock.  i want to work back up to the 4.3GHz overclock both to reduce the bottleneck of this old CPU, and to see whether it was actually the OC that the card didn't like (versus just some buried BIOS setting that i forgot about).  also, as discussed below, my mobo may not support PCIe 3.0 at all (a subsequent revision did), which may have made the 4.0 fallback even less reliable over the cable.
 
here's the card in the old case with the vertical mount - pity i had to switch, as it actually fit in there.  notice that i had to rotate the CPU cooler 90 degrees to make room for the vertical mount.

 
here's everything moved into the new temporary case.  one bonus about moving cases is that there's much better airflow with the layout and cable management.  i still need to tweak the airflow, and i might return the CPU cooler to its original position (note that i had to remove the red cap from one DIMM so that the cooler wouldn't press on it too much).

 

riku98523
Sometimes riser cables might not be getting a good connection on one or both ends. It's even possible that it has an ok enough connection for the 1080 but no the 3080 as weird as that could be. Or the 3080 isn't sitting on it's end property (make sure it's pushed all the way in from front to back). Riser cables also have to transfer power from the mb to the card and it could be that the 3080 is maybe pulling more from the mb than the 1080 and the cable can't handle it.

 
yes, the riser cable market seems really variable in quality and compatibility.  like, 3.0 and 4.0 extensions are dimensionally identical but vary on cable impedance or something.
 

Cool GTX
Q-LED indicators ?

 
the LED indicators and the POST beeps were both being a bit inconsistent.  often the VGA error light would be off (no error detected) while the POST beep would report a general hardware issue (not very helpful, heh).
 

ex90ranger
wile I don't have any advice on troubleshooting, I can tell you that I am running a 3080 FTW3 Ultra on a riser cable with an older X99 board and 6850k.  my card runs at 3.0 perfectly fine and I didn't have to do anything to get there.  the riser I am using is the Phantex Vertical mount kit.  

 
interesting!  so maybe a 3.0 cable isn't really a problem, it's just this 3.0 cable.
 

Hillguy
Sorry to say but I don't think  your MB supports pcie 3.0 ,  there were bios updates for the p67's to upgrade to 3.0 that required a Sandy Bridge cpu ( which you have ) but from what I can find the P8P67 Pro was left out of the update list. 

 
ahhh thanks for finding that.  i noticed that GPU-Z was reporting PCIe 2.0 and thought it might be an error, and i had heard about PCIe 3.0 on some P67-series.  it was so long ago, though, that i probably forgot that my board wasn't supported.  at least it properly supports x16 now!

ex90ranger
Interesting.  I do have random BIOS problems with my system as well with posting.  but most of the problems are around the memory when I have my OC turned on.  I have honestly never seen a problem with the GPU and OC causing a system to not post correctly.  I will add that to my store of knowledge

so, that was one confusing thing: sometimes i would notice that there were POST error beeps, LED diag lights, and no video, but also the PC would appear to boot because the hard drive light would be blinking away normally.  other times, there would be POST & LED errors, no video, and no drive activity.  i think that inconsistency may have to do with issues for both the cable and BIOS settings.
 
one possible OC issue is that, at least for the P67 and/or Sandy Bridge procs is that a certain memory overclock setting also changes the PCI bus clock speed.  however, setting that back to the stock multiplier did not eliminate the issue.  i think it might just be some weird esoteric bus or OC setting buried in the EFI menus; when i get some time, i'm going to look more closely at my saved OC settings and compare them to the defaults.

slayertx
Just wanna make sure you put your mobo in 3.0 mode and not auto right? Many of us that use vertical GPU's have to do this on amd boards.

Should check your post earlier. Spent a whole night on trying to install the 3060 ti. Changed cables, plugged/unplugged GPU, freshly installed the driver many times ...  It was working fine for an hour. After Windows 10 installed several updates, the system crashed again. Finally, I figured out at 2AM this morning that I had to set it to PCIe 3.0 in BIOS for the EVGA vertical mount.