Pc won't startup with 2 gpu

[PaulRaven]

Hi, recently I purchased 2 gtx 980 ti and a new psu.

Each card works perfectly when not seated together on the mobo.

My specs:
Mobo: msi p67-gd65
Cpu:i5 2500k@4.2ghz
12 gb ram
Psu: Corsair ax1200i

I can use both cards in both pci-e slots alone but when I try to connect both of them and try to startup my pc, it opens then shutsdown and keeps doing this until I switch psu off.

My bios is up to date, all drivers are up to date and I am using windows 10. I tried flashing bios again, resetting bios, removing cmos and installing it again. I know my cpu and mobo is old gonna change them in 2 months but I want to use my gpus until then. Any other advices?

 

[Thugginator]

Can you describe what you mean by "it opens and then shutsdown".
I have some ideas;
1. the 1200w might not be able to handle both cards + overclocking the cpu
2. motherboard might just might not be able to regulate all that power.
3. psu is dying

 

[PaulRaven]

I mean when I hit the power button, the fans start spinning for 2 sec then stops (pc shutsdown) then starts again by its own (without pressing power button) and also I undo my OC and try again but still no luck

Well I think 1200w is a little bit overkill for 2 g1 gaming gtx 980 ti and OCed 2500k (my cpu should be drawing 120w max I guess and 2 gpu's 258w by each according to some review under normal load not heavy load)

I am suspecting from my mobo too. Maybe its pci-e slots not providing enough voltage for second card don't know actually.

The psu is new, not brand new but only 1 year old. Used to power two 290 reference cards (my friend's cards)

The only thing I didn't try is overvolting pci-e slots. I don't know how to actually

 

[PaulRaven]

I guess I found the problem but still don't know if it is true. I am posting it here if some one looks into same situation as mine.

My mobo has 1 pci-e 2.0 x16 and 1 pci-e 2.0 x8 and gtx 980 ti wants pci-e 3.0. People say pci-e 3.0 x8 is equal to pci-e 2.0 x16 and the Nvidia's minimum required pci-e slot is 3.0 x8 (I guess so). So with the second gpu, my second pci-e 2.0 slot acts like pci-e 3.0 x4 I guess and since I am using i5 2500k (which has Max of PCI Express Lanes 16) I cannot match the required pci-e slot speed and this causes my pc to don't even startup.

I will buy an intel i7 5820k with MSI X99A SLI PLUS mobo. I am open to any other recommendations though.

 

[Thugginator]

I guess I found the problem but still don't know if it is true. I am posting it here if some one looks into same situation as mine.

My mobo has 1 pci-e 2.0 x16 and 1 pci-e 2.0 x8 and gtx 980 ti wants pci-e 3.0. People say pci-e 3.0 x8 is equal to pci-e 2.0 x16 and the Nvidia's minimum required pci-e slot is 3.0 x8 (I guess so). So with the second gpu, my second pci-e 2.0 slot acts like pci-e 3.0 x4 I guess and since I am using i5 2500k (which has Max of PCI Express Lanes 16) I cannot match the required pci-e slot speed and this causes my pc to don't even startup.

I will buy an intel i7 5820k with MSI X99A SLI PLUS mobo. I am open to any other recommendations though.

Great find, i had the same idea but couldn't find any sources. Keep me updated. Cheers

 

[PaulRaven]

Used intel's ark website to check. You may need it in the future. Thank you for your fast replies though.

 

[Thugginator]

Used intel's ark website to check. You may need it in the future. Thank you for your fast replies though.

Thanks for the info. Hope you have luck with the new setup.