Question Is my GPU or psu faulty


Sep 5, 2017
Hi all I bought myself a gtx 970 Palit Jetstream secondhand. I had a gtx 750ti, yesterday night with my gtx 750ti while busy on my pc the screen made some small offset color stripes and heard a weird noise and pc totally shut down immediately, first inspected and saw nothing weird and started it up all was well again, got today my 970 and sold my 750ti installed my 970 but pc won't post on screen in the one pci slot it will give me about 4 continuous beeps it is so fast I allmost can't count it and in my second pci slot it will give me 2 short beeps and one long beep, all google show is 2 long beeps and one short beep nothing about visa versa the thing with the gtx 750ti it only had 1 x 6 pin connecter and the 970 have 2 x 6pin connecters could the psu maybe be faulty or the gpu that I bought secondhand, the guy told me he tested it before he sended it and it worked unfortunately I didn't asked him to send me some pics for proof😔. If I plug out the gpu and only connect to mobo it is posting on the screen.

My specs.
Gigabyte GA-B75M-D3H
12 GIG Ram two sticks is Kingston KVR 4GB 1333 and one stick Transcend 4gb 1333
I7 2600
Psu - Gigabyte GE-P720A-C2
GPU - Palit GTX 970 4gb Jetsream