I have Evga GTX 1070 FTW. When I moved AMD 6950 Crossfire to  1070 FTW, while playing CSGO it restarts suddenly. Without any error messages. It occurs only using 1070. When I put my old 6950s(single and/or CF) not a little issue happens. (I'm using DDU when switching cards)

There aren't any heat,power or bottleneck or OC issues.

MY PC:
i7 2600K @4.5GHz 1.29V (stable and cool for hours of prime95 etc.)
Asus P8P67 Pro mobo.
Corsair Vengeance DDR3 1600MHz CL8 Dual Channel 16GB(2x8GB)
Thermaltake Frio CPU cooler
Evga GTX 1070 FTW with custom fan curve. While playing CSGO %55 fans @30-35 degrees Celcius.
Corsair HX850 PSU 12V single rail 70A.
840 Evo 120GB SSD, raid0 HDD...
HAF X case with %100 fan speed.

Windows 10 1607 14393.447
Nvidia drivers between 362-375.95
 
What I tried to solve:
 
Format Windows 10 and fresh install
Change drivers
Delete game, downloaded again, tried it
Change settings in game/Nvidia Control Panel
Different fan speeds(Auto, Manuel %40-55-60-75-80-100)
Update BIOS(both mobo and graphichs card)
Stock freqs in all over the system
downclock
 
They all done almost nothing. Pc restarts almost every match. But I noticed that when I use DSR to play in higher resolutions, it restarts in shorter time. 4K+60fps limit(from console fps_max 60) I can play "up to" 10 mins. Generally at 4K 2-3mins, at 1080p sometimes 30-40 mins, sometimes 5mins. When I use disable multi core processor setting in game settings, I get lower fps(as expected) and play longer without restart. But it restarts anyway. Actually it shutdown then boot up.
 
I didn't tried playing CSGO with my GTX 1070 on another pc. Because other pc has APU system and VS450 PSU. I'm not sure if it can handle that power or not. I as wrote, playing CSGO is only issue that I seen so far.
 
Before 1070FTW I had 2 1070SCs. They both had serious Coil whine and when they restart(they restarts almost every game) their backplate was too hot to touch but FTW doesn't. FTW's backplate is warm while on full load. 

Sajin

Firaristt
It occurs only using 1070. When I put my old 6950s(single and/or CF) not a little issue happens.

That pretty much sums it up for me. The 1070 is causing the problem.

What can I do then? That's my 3rd Evga GTX 1070 card. Should I open RMA? Or wait for thermal pads? By the way, I bought it on amazon.com but it's been over a month. So amazon won't provide return or replace in my two cents. Else from Evga EU, if there will be replacement, I'll probably have to pay custom tax again(~80$, %20). You may know that, Turkey had an coup attemp and after that our customs become very strict. What should I do then?