Gpu doesn't work on pcie 3.0

[basics]

Hello guys, again i turn to you.
My rig: i5 3570k, gtx 760 evga sc 2gb, z77 pro3 mobo, 500w psu, 1 x hdd, 1 x sdd, 2 x 4gb ram.

The gpu works fine on the second pci slot, but doesn`t work on the pcie 3.0. Computer starts but instead of seeing bios the monitor doesn`t get any signal. At some point i managed to start the gpu on pcie 3.0 but went dead again after shutting down comp. Also whenever it started on that slot i got a lot of problems after installing the gpu drivers. mostly freeze and bsod.

Things i tried: Cleaning, everything. Changed mobo(initially this problem was on z77 pro4 then the mobo died and i could only replace it with z77 pro3). Cleaned cpu(ivy bridge, i was starting to think some pins are either bad or dusty), changed psu, messed up with bios settings(it is up to date).

Now i`m left with one of 2 things, either the cpu has bad pins or the gpu is faulty(pins or otherwise).

Have you ever got this problem? What can i still try? My luck could be the fact that i still have 3 months of warranty for my gpu.

 

[Tradesman1]

Do you have the latest BIOS and mobo drivers? Have you tried with a different PSU?

 

[basics]

Do you have the latest BIOS and mobo drivers? Have you tried with a different PSU?

Yes to all. The only things i didn`t change was the actual gpu and cpu. Everything else was swapped and work properly. It must be the gpu. I`ll just send it back in the near future, 1-2 weeks.

I don`t understand the random starts, for example, i reseat the gpu and it sometimes starts, but with the problems i mention earlier. Sometimes after reseat the monitor doesn`t get any signal. The hdd led stays on for about 3-4 seconds and goes black, power led stays on. When i talk about reseat i only talking about the pcie 3.0 capable slot.

Here`s another piece of the puzzle. The slot was set on pcie 2.0x16 gpu started, windows started, me glad. Went to bios, changed the slot to pcie 3.0 and the above mentioned problem occurred. So i reseated the gpu on the second slot, then went to bios, changed the first slot to pcie 2.0, reseated the card and ... same problem. I don`t know how to tackle this problem. What else should i try.