My spec's:
i7-4790K OC'd to 4.6Ghz @ 1.260v
16gb DDR3 2400Mhz memory,
Asus Z97 Pro Gamer motherboard
Corsair 850w psu
Windows 10
 
I recently bought a EVGA 1080ti FTW3 and was happy with it for the first day, just doing stanard tests, benchmarks and games and it ran great. However I attempted to overclock the card the following day and experienced something I haven't seen before. I have upgraded from card to card numerous times and I'm used to troubleshooting but I am stumped on this!
If I touch the core clock or memory clock i get really low frame rates in any 3D application I am running, however the card doesn't reduce its clocks speeds while this is happening and temps remain in the high 50's (my card doesn't really go any higher than 59/60 degrees under load) so it lloks, by the graphs that my card is running great. If I stop the application the card does what it is suppoed to do and cools down. If I start an application again the problem with low frames remain. I restart the driver with WIN+SHIFT+CNTL+B it doesn't fix the problem.
Whilst the frames are low my other parts are doing ok, my CPU doesn't bottleneck any game or application I use, my RAM is never full and my drivers are SSD's.
 
I have tried increasing the voltage on the card, no change.
Reinstall driver with DDU and latest NVIDIA driver,
Check that the card is seated and plugged in with both power sockets,
Use GPU-Z to see any faults, nothing,
Looked on these forums, tomshardware, NVIDIA with nothing I can find, no one else seems to have experinced this problem.
 
Funny thing is if I restart my computer the problem goes away! But returns if I start an application again with the card overclocked. It seems unlikely that I have a card that can't be overclocked by even 10Mhz!
I'm really confused by whats going on. Any help or suggestions would be great.

Yes it does! Sorry should have stated that I tried the OC bios

Yes both, I also cannot understand why EVGA doesn't let MSI Afterburner control all 3 fans!

Unfortunately I don’t have another system to try it on! I will put my old 1080 ftw2 in and test that, but the problem only started to occur once I put the ti in the system

This happened prior to using pocx! I got the card started using pocx and then it started! I will try your suggestion and update tomorrow, it’s the evening in the UK

Yeah real quick.. how old is your psu?

So the card is really screwing with my system this morning! Computer would not load from UEFI, hanging on the MOBO splash screen and running really slow! Pulled it out, put in my old 1080 ftw and all back to normal! Think I’ll be returning the card! Shame though, it had great power!

Yeah replace/exchange the GPU. Hopefully ya can.

Thanks for all the replies guys.
 
Now I am having issues with BIOS after I removed the card! I'll return it to Amazon as I only got it 4 days ago. Anyone known anything about computer shut downs when changing setting in the BIOS?? 

I had assumed that you got it used - my bad! Definitely return it to Amazon and get a replacement. :)

theOzman84
It’s doesnt restart from any bios change! It powers off and then becomes unresponsive for about a minute. I have switch off the PSU and let the residual power leave the board before I can switc the PSU on and boot up

Is that with the 1080 reinstalled, the 1080 Ti or both? You need to be more clear in describing what you are doing and what you're testing. When is the last time you changed the CMOS battery on the board? If it's the original, you're way past time.

Sorry, 
 
I have taken the ti out and have returned to my original 1080 ftw. 
My system boots and has no issues getting to windows. The problem comes when I change any bios setting. Once I save and quit my PC instantly shuts down and then attempts to power back on for a split second before dying. It is then unresponsive. To get it to power up again I have to turn the PSU off, wait for the residual power to leave the board (I watch the standby LED until it goes out). Once the LED goes out I flip the switch on my PSU and the computer can boot up normally. 

I haven't ever done it! I will order one now though. 
 
Any settings I change. Once I save and exit the system shuts down, it didn't before, it used to restart but without powering off. Once its dead it is unresponsive.

Ill pick one up from my local market in the UK.
 
Thanks for the help guys.

Did you turn Windows 10 Fast Startup OFF ?  ( when upgrading drivers, firmware or hardware )
 
           With Windows 10 there is a new “hybrid” startup mode that should cut down on boot up times.

           It does this by putting the PC into hibernation instead of fully shutting down."


Windows Central - How to disable Windows 10 fast startup (and why you'd want to)

How-to Geek The Pros and Cons of Windows 10’s “Fast Startup” Mode
 
---------------
BIOS settings:


Fast Boot On or Off ?
 
Primary Display - GPU card set as primary ?
 
Is your MB BIOS set to "Auto OC" ?
 
CSM ?
 
Secure Boot ?