o_0 no

I mean... Well no. There is no 5V rail in the PCIe bus, so +5VSB can't be powering anything in the card.

The card has access to +3.3V and +12V from the PCIe slot and the PCIe power cables. Neither of those rails should be powered on after the computer is shut off.

What power supply do you have?

I have a corsair ax760i for PSU

Thanks. I will try this later tonight after work

What happens if you turn off the Power Supply?
 Your MB LED should not be showing the Letter C.

jamieplz

GTXJackBauer
Go to your BIOS settings to enable EU compliance.  It will power off anything on your MB if the issue exists but at the same time, it shouldn't be lit while shutdown so there can be a existing issue there OR the MB's LED lights are creating the illusion and illuminating the GPU's shroud, etc.

I have tried enabling both the ERP mode (european power standards) and Dark Mode, and the graphics card's LEDs+Logo are still on after shutdown. See attached image.
 
I am wondering if this is perhaps a bug in the card's BIOS as bizarrely if I enable the LED settings as 'breathing' or 'rainbow' these persist when the PC is shutdown.
 
Anyone else on this forum with a 1080ti SC2 that has similar issue? 

If ERP is enabled, there shouldn't be any LEDs on at all.  This is interesting and thanks for posting a pic.

bcavnaugh

jamieplz

bcavnaugh
What happens if you turn off the Power Supply?
 Your MB LED should not me showing the Letter C
 

As stated in the original post turning off the PSU via its switch kills the power completely (same effect as wall switch)
 
As for the "C" this has always been there on the motherboard. I never been able to find out what that means as its not covered in the motherboard manual. Do you know what this means?

Maybe a short somewhere, you need another Z170 FTW owner to chime in and I will chime out for now.

Thanks. To answer your second question from before the cables are plugged in correctly :) Just looks out of place in the photo due to the way the cables are. I know from own experience if this is not plugged in correctly your system won't even post.

GTXJackBauer
Sometimes when getting custom PSU cables, you could have either a crossed cable or just a bad cable.  Worse comes to worst, use the original cables that came with the PSU and just connect the bare essentials just to see if these LEDs turn off while having ERP mode enabled and hope that code gets cleared.

Thanks for that suggestion - I might try that although never had any problems with my cablemod cables before, in this system and others.
 
I have raised a support ticket with EVGA about it so will see what they say/suggest. If I get a fix I will post back on this forum otherwise I can happily live with this.

Quad5Ny

jamieplz
SOLVED - the "C" issue on the motherboard was in fact my problem.
 
I did some googling and stumbled across a YouTube video where another guy had a EVGA Z170 board and the same C code displayed on his motherboard (in his case his system wouldn't POST but I did not have that issue). He replaced his displayport cables to resolve that problem and the C code went away.
 
^^ I did the same thing and bought a new displayport cable, and the C code went away. At the same time the LEDs are now off when I power my system down so this has resolved my problem. 
 
Thanks again to all on this thread who helped me.

Well crap I wouldn't have even thought that was possible. I guess you learn something every day.

Yeah the guy on the video said it took him ages to figure out it was some grounding issue and his cable causing it. I too would have never had guessed a cable could do that so yes have learned something new 

Can you link a video that you used to solve this problem? Can be priv if you perefer

ViBen
Can you link a video that you used to solve this problem? Can be priv if you perefer

https://youtu.be/FYcQ9hZtq_g

In the past, I also experienced similar with a DP 20 pin cable used for the connection. As the 20th pin SHOULD NOT be wired / is an obsolete pin in newer DP standards, very old or uncertified DP cables can cause a short on the GPU that causes the LEDs to be powered even after shutting down the PC.

Angier_1985
In the past, I also experienced similar with a DP 20 pin cable used for the connection. As the 20th pin SHOULD NOT be wired / is an obsolete pin in newer DP standards, very old or uncertified DP cables can cause a short on the GPU that causes the LEDs to be powered even after shutting down the PC.

I have heard the same thing. I have also heard it is not an issue on Windows 10... 
 
According to displayport.org there is no difference in cables, old or new. However, it refers to bandwidth, not physical wiring of said pins. My DP cable is very old and is still listed at DP (VESA) certified.
 
It would be really nice if we can get a real answer on this given the amount of rumors and bunk info there seems to be floating around about pin 20. Not saying your wrong, just saying all the info I've read has come from reviewers copying and pasting what they heard from other reviewers when there seems to be another factor involved.

Could be knockoff DP cables that are cheaply made, who knows.

Sorry to necro this thread.
But something interesting happened to me.
The same problem,
But it happened when I changed from my Red Sleeved OEM EVGA cables set (750W G3 + PN 100-CR-1300-B9) to white sleeved cables from CableMods (specific for the G3 series)

I did a complete shutdown (unplugged PSU from wall socket) and the leds on my FTW3 stayed light on (like in a half phase energy).
Immediately I remembered about this issue, and unplugged the Displayport cable, and voilá. Lights went off.

I will replace the GPU cables again to see how it goes and will report back to add another possible cause to this issue.