PCIEx16 3D crash problem , PCIEx8 3D all Ok

Hello



Intel I7-4790K

Asus Maximus VII Ranger

Gigabyte GTX 960 Windforce 2x oc

Power Corsair CS750M

G-skil 8 Gbs ram (2x4Gbs)



My new pc has a problem , since it was build , it works fine using windows 7 (folders , pictures..all) and on the internet and watching videos ...

But running a more demanding 3d game or benchmark the nvidia driver crash (nvidia Display driver stopped responding and has recovered) after some seconds ,

for example on Valley Benchmark 1.0 ,Heaven Benchmark 4.0 ,3DMark ,3DMark 11 and others .



Did many tests without luck :

Installed all nvidia drivers (using Display Driver Uninstaller before install the new drivers) .

Installed chipset update, sound update, Intel(R) Management Engine Interface update (<<this is needed???) , AMDA00_Win7-8-8-1_V1010 something about USB's , so that all the device manager can be without the yellow interrogation symbols "?"

Did CPU stress test with IntelBurnTest 2.54 , all ok .

Did a memory test with memtest86+-4.20 , 3 pass's , all ok .

Did 3 motherboard bios updates .

Tried 2 screens , 1 dvi-i to dvi-i , 1 dvi-d to hdmi

Tried hdmi to hdmi but i get a very red screen and a look of just 256 colors in windows , i will talk about this later<<<<<

Tried many different settings in the bios , UEFI .

And alot more things that i don't remember now...



After alot of tests , changes , updates :

i have found that this problem happens with the card installed in the PCIEx16 slot ,

But works ok if its in the PCIEx8 slot .

In the PCIEx8 works very well , theres no nvidia driver crashs , theres good fps on Valley and heaven (the tests i use more) .





After all this , whats the problem ?

•Motherboard PCIEx16 slot Faulty ?

•CPU is Faulty ?

(i read somewhere that the CPU controls the PCIEx16 lane . About the x8 lane ,the CPU doesn't control the PCIEx8 lane or it does ? )

•Video Card is Faulty ?

Is possible that a video card it self works ok in the PCIEx8 slot but dont work in the PCIEx16 slot ? (because its somehow damaged using x16 "system" ? )

•Other thing ?



I tested a old card(7900GS) in the PCIEx16 slot and works without crashs but that card is not so demanding as a GTX 960 tho

(The 7900GS i tried it in the Valley test but the fps were very low , but the driver didn't crashed. I need try it again but in the game LFS for example to see if crashs or not)



Any other tests i should do ?

What you guys think about this?



Thanks

PCIEx16 3D crash problem , PCIEx8 3D all Ok