Sounds like your gpu may not be getting good clean stable voltage. Those 5 LED's are voltage indicator lights that can help you diagnose voltage problems with your video card. With the gpu fans facing towards you and the power connectors facing up, the LEDs are, from left to right:

GPU - This indicates if voltage to the video card's GPU is good
MEM - This indicates if voltage to the video card's memory is good
PLL - This indicates if the voltage for auxillary components such as fans, LEDs, etc. is good
3.3V - This indicates if the voltage supplied from the motherboard via PCIe slot is good
12V - This indicates if the voltage from the 12v input from the power supply is good

If any of these LED's are not lighting up, it indicates a voltage issue with that component or source.
 
Note: This it how it was on older gen cards. Pretty sure it's the same for newer gen cards as well.

InferionThat's been there since I had a ...1080ti.

A typo ?

Inferion
That's been there since I had a GTX 580 Classified, 980ti and 1080 Classy.
 
If the card runs full load that Left LED will bright up. If it's on idle it Dims down a bit. I had those on my 580 Classy also before and my 980ti Classy.
 
As Saijin said its an Indicator for your GPU Voltage. I think its also on every Classified Manual. 

Awesome thanks for the info, Thought I had to RMA.

Sajin
The led shouldn't dim at idle conditions. A co-worker of mine had me build him a rig a long time ago with a 780 classified. The gpu led didn't dim down on idle/brighten up when under a load.

The LED according to other 1080 Classified owners that I've talked to on another forum dims once the GPU voltage drops to around 0.600v but if you have "Prefer Maximum Performance" selected in the Nvidia control panel the voltage never goes below 0.800v so the LED never dims so your friend either probably never noticed the 1st LED dimming or he had "Prefer Maximum Performance" selected in the Nvidia control panel.

Sajinetup his computer back then. I remember the led not dimming at idle. I'm going to ask a evga tech to review this thread.

You do that, But if it is a fault then EVGA have a crap load of faulty GPU LED's on their hands because everyone I've talked to who has a Classified has reported the exact same.

EVGATech_ChristianB
The LED should stay steady under any load. However, any fluctuation of power may cause the LED to dim so it's possible that the power running through the card is not stable. This could be the result of, unfortunately, a faulty LED/card or power supply. I'd suggest trying different PCI-E power connectors from the PSU or another PSU. An alternate suggestion would be to test the card in another computer.

Well then you sent out a metric butt ton of faulty GPU's then as everyone who I've spoken to who has Classified GPU's has this same issue when the voltage drops below 0.800v.

Sajin
Pascal titan x idle voltage results with global power management set to adaptive/prefer maximum performance:
 
Adaptive: 625mv.
Max performance: 625mv.
 
Notes: Restarted the computer after each power mode change.

Maybe I'm being a bit dumb here but what does a Titan XP which does not have the 5 little white LED's have to do with the Classified ? They are completely different board layouts as well.

Sajin
I did the test to show that prefer max performance doesn't affect the idle voltages.

You have to remember that the Titan XP is GP102 and not the same GPU as the 1080 i.e GP104, Completely different dies.

Sajin
You're correct, however, I don't see the nvidia driver forcing 800mv on only a 1080 gpu. If the prefer maximum performance option affected idle voltages I would have seen a change on my end.

The PMP option also ups core clock, Mine stays at 1700 when this option is enabled so maybe this could explain the 0.800 v instead of 0.600 at idle ?
 
Pics for comparison -
 

 

Sajin
That's interesting. Looks like we found another driver bug that affects 1080 gpu's. Do you see the same readings using msi afterburner? Make sure you have all 3d accelerated apps closed when taking a reading.

Yep it's in Afterburner too, No other programs open :)
 
 

Sajin
Make sure 2d apps are closed too.

Everything was closed minus Afterburner or PX.

Dicehunter

Sajin
Make sure 2d apps are closed too.

Everything was closed minus Afterburner or PX.

Do you get the same results even after rebooting your computer? How about after performing a clean boot (#1) of windows?

Dicehunter

Sajin
Do you get the same results even after rebooting your computer? How about after performing a clean boot (#1) of windows?

Ok just did the clean boot and it appears that Corsair CUE and Link are causing the high idle clocks and volts, Without them they go down to what you posted earlier, Nice 1 for posting that guide link BTW.
 
Would still like get to the bottom of this LED issue as lots of people have the same issue when going below 0.800v that the 1st LED gets a little dim.
 

Glad to hear that. 
 
Guess it's time to try some of Christian's suggestions.

Sajin

Dicehunter

Inferion
That's been there since I had a GTX 580 Classified, 980ti and 1080 Classy.
 
If the card runs full load that Left LED will bright up. If it's on idle it Dims down a bit. I had those on my 580 Classy also before and my 980ti Classy.
 
As Saijin said its an Indicator for your GPU Voltage. I think its also on every Classified Manual. 

Awesome thanks for the info, Thought I had to RMA.

The led shouldn't dim at idle conditions. A co-worker of mine had me build him a rig a long time ago with a 780 classified. The gpu led didn't dim down on idle/brighten up when under a load.

Welp, Saijin is Right Tested again my 980ti Classy it didn't dim down. But my 2 old 580 Classy does and my current 1080 Classy. Hmm such a weird LED. Waiting for more info about this then.

I also know 2 people who say their Classified 1080  led light is dimmer until a load is put on the card from gaming or benching...... , using POCX
 
 
running either  adaptive or prefer max perf in driver controls , doesn't matter