Black artifacts/Horizontal lines flickering when gaming with my 1080ti [Video]

[iltarix951025]

So I bought a second hand 1080ti recently, and I'm seeing some artifacts and horizontal lines/boxes flickering while gaming, I tried underclock the VRAM but it's still there seems like. The driver is fully re-installed, and I tried different cable/port, and even a different PCI-E slot on my mother board, it's still the same thing. Does anyone know what's going on ?

My spec:
i7-4790k OC @ 4.8Ghz 1.29v
16gb DDR4 1600Mhz
MSI 1080ti Duke OC
MSI z97 Gaming 7
HX750 PSU (Could this related to PSU cables? Cuz my old 980ti 8pin connector was really tightly connected, so I had to use some force to remove them I remember)

It happens in almost all the graphical intensive games, the only game so far that I cannot see any artifacts is Dota2, but everything else has similar issue.
Here is a video:https://youtu.be/N9xkyo1gQrA

 

[Peter Martin]

Artifacts are a sign of hardware failure

 

[geofelt]

Such symptoms could be caused by insufficient power delivery.
See if you can't test with a known good psu of sufficient power.

Otherwise, I would think the card you bought is faulty.
Return the card.

 

[Serinox]

If you still have your old gpu, try changing gpus. Sounds like you bought a defective gpu.