GTX 970 not detected

[_LUCU_]

Hej, i just got a new gpu, gtx 970 strix 4gb The pc boots and post with it, but after 30 or so i loses signal. i have managed to get in device manager and see the gpu is not detected. My mobo is a asus z97-A psu is a corsair 750W so no problem there. My pc used to run with sli gtx 960 and i have uninstalled all the previous drivers. I have also tried the gpu in a z170 with no different result. i also tried disable onboard graphic card and in bios booting from peg and pci-e with no help

i dont really know what else too try, and i dont really wanna send it in for repair, that if it works for them it gonna cost quiet alot :/
Mvh L

 

[renz496]

so even on other mobo the card still cannot be detected properly? brand new or used?