I have a 1080ti FTW3 Elite that's running really hot all of a sudden, hitting 91 (with aggressive fan curve) in CODMW and a few other games. I have turned debug mode on in Nvidia CPL and doesn't go above 84, runs like a new card. Higher fps. But debug setting resets after a reboot so I downclocked the core by 200mhz, (which is the max amount i can do inside precision) which i assume is round about factory settings for a normal 1080ti, saved as a profile, but the temps rise again. Ive went back a few drivers, used old precision, DDU'd, cleaned pc of any dust, no dust anywhere, card was pretty clean anyway - made no difference.  Is debug mode doing anything else other than downclocking? Power supply is RMX850. I am running card on one power lead that splits into 2, should I be using 2 seperate power leads? Any idea what could be causing this. Warranty expired would you believe 12th May . Any help greatly appreciated.
 
EDIT: My case is Phanteks Evolv, 2 fans on the front intake, cpu aio cooler up top and 1 exhaust fan at the back. CPU (3770k) overclocked to 4.2 doesn't hit any more than 70 when playing CODMW.

See Why does my EVGA graphics card run hot? in the EVGA FAQs..Debug Mode just downclocks..Capping FPS may help significantly..Using two seperate PCIe power cables is recommended for high-powered (225W+) cards.

You might consider changing the Thermal Paste on the GPU chip with some good stuff like Thermal Grizzly Kryonaut (12.5 W/mk Thermal Conductivity) or MX-4 (8.5 W/mK Thermal Conductivity)..I would.
 
If you really wanna do it up like a boss, use Thermal Grizzly Conductonaut (73 W/mk Thermal Conductivity)..But that's liquid metal and precautions must be observed when using liquid metal TIM.
 
See the EVGA 1080 Ti FTW3 Tear-Down video from Gamers Nexus.

Thanks for the help. I've reset the OC on my CPU - makes no difference. Case fans were on 100% already. Side panel off, no real temp difference. Going to add another power cable, I've ordered some mx-4 and a toolkit to take my card apart and renew the thermal paste, may as well do my CPU while I'm at at it. Wish me luck.

clean well light work space & a small container (zip-lock bag) so you don't loose the tiny screws.  If your working over carpet ... have a magnet handy
 
90% alcohol & lint free pads (paper coffee filters) & cotton swabs to clean with
 
Look on the web for some guides
 
GL

If replacing the thermal compound doesn't resolve your issues, please reach out to us directly for further troubleshooting or any available warranty options.

 
 
Following up, if the thermal paste replacement has resolved the issue, it most likely will.  If you find the thermal pads need to be replaced: https://www.evga.com/support/faq/FAQdetails.aspx?faqid=59738
 
Regards,
EVGA