Hey guys,
 
I had some help from member here a week or two ago and thought the issues with my 1070 SC had been fixed, but they're back.
If I play a demanding game for over an hour I start to get major frame drops. This is even after applying the BIOS update which dropped
the gpu load temps from 70 to 60c. 
 
I can be playing at 120-150 fps and then out of nowhere it drops to 50-60 causing stutters, then
back up to normal. This goes on until I turn off the computer, wait for a while and start playing again. Things
are good for 45 minutes to an hour, then it begins to act up which leads me to think it's a heating issue. My case is
always kept cool with plenty of airflow.
 
This isn't the only problem with the card since I have a weird oval vignette at the edges of my screen that shows up randomly in DirectX games.
It sort of looks like color banding on a bad tn panel monitor. Not sure if it's driver related or not since it always seems to show up around the time the card starts to stutter.
 
Think I might have a lemon but just wanted to see if anyone might have any suggestions. I'm afraid that running the card without
the thermal pads has already damaged it.
 
 

Almost sounds like VRAM issues.  Either overheating or just defective RAM modules.
 
I'd call EVGA and explain the issue.  Attach some images if you can.

Have you tested with a different Cable?
The weird oval vignette looks more like a Monitor or Cable issue.

Dragnink
Hey guys,
 
I had some help from member here a week or two ago and thought the issues with my 1070 SC had been fixed, but they're back.
If I play a demanding game for over an hour I start to get major frame drops. This is even after applying the BIOS update which dropped
the gpu load temps from 70 to 60c. 
 
I can be playing at 120-150 fps and then out of nowhere it drops to 50-60 causing stutters, then
back up to normal. This goes on until I turn off the computer, wait for a while and start playing again. Things
are good for 45 minutes to an hour, then it begins to act up which leads me to think it's a heating issue. My case is
always kept cool with plenty of airflow.
 
This isn't the only problem with the card since I have a weird oval vignette at the edges of my screen that shows up randomly in DirectX games.
It sort of looks like color banding on a bad tn panel monitor. Not sure if it's driver related or not since it always seems to show up around the time the card starts to stutter.
 
Think I might have a lemon but just wanted to see if anyone might have any suggestions. I'm afraid that running the card without
the thermal pads has already damaged it.
 
 

Hello - sorry to hear about your issue :( - it is an unfortunate thing, but lemons happen. if this is a new Issue that developed when you changed your video card - I would lean towards the card having the issue (assuming you did a fresh windows install, all the power cables are plugged in properly, and the card is seated in the slot correctly) - also what happens if you underclock your card a few hundred MHZ? do you still see the same issues? 
My best suggestion would be to call Evga, and send the card back to get it fixed or replaced. GTX 1070 was supposed to be a 375$ card (with all the founders edition bullcrap) and many manufactures charged a premium on top of that cost, so it will be in your best interest to get a properly working card. You also mentioned that your temp dropped from 70C to 60C, but I am 100% confident that it is your core temp that dropped, and not the VRAM temp - If you have a digital IR meter, you can check the VRAM temp, I dont think any applications tell you the Vram temps
 
GL