MSI Z97 Gaming 5 and GPU problem

[brutalebent]

Hey there mates

Got the following PC from a gamer for free, who surmised it was probably the GFX that was dead.

i7-4790k - Watercooled (one of those double fanned corsair coolers)
MSI Z97 Gaming 5
32 GB ram Hyper Beast
Geforce 780 Ti

I got a 7970 Sapphire Vapor-X (tested if it works in my own PC), but when I install it and boot up, it initializes the display, but it's still just black. Can still reset ALT+CTRL+DEL, so I figure the system is running, just no display output.

iGPU works fine, and I can see BIOS when starting then.

Tested all 3 PCIe sockets, another PSU (Corsair TX850), tested ram, reset CMOS, updated BIOS - nothing worked.

Now, the real kicker - I put in an old Sapphire Radeon HD6850. Works fine.
Then I tried my 1080 Ti, because why not, and it works fine too...

Back to the 7970, that still works in my rig, and it doesn't work.

Sorry for the language, but the actual ****? I'm stumped. Which is why I finally caved in, made an account here, and ask more tech savvy people. 😉

Grasping for straws here: While I haven't dared putting the 780 Ti in my rig for testing, for fear of it killing/damaging my MB/CPU too, can it be that one of the PCI lanes are "broken", and the 780 Ti/7970 happens to use that, and the 6850 and 1080 Ti doesn't?

 

[Saga Lout]

Hello and welcome to Tom's Hardware.

Pardon my editing of your post but I'm sure you'll appreciate we have some very young readers so we keep our language clean.

 

[Saga Lout]

I've removed your Bump post - we don't allow those. Tom's is global so time zones are a big factor.

I've also called up the cavalry of folks who'll be able to help you

 

[Darkbreeze]

Unlikely. Those are all PCIE 300 cards except the HD6850 which is 2.1, but they are all x16 and they all use the same pin configuration.

What power supply is in this gifted system? Exact model number.

 

[brutalebent]

Alright, sorry for the mistakes, and thanks for helping me out! 😉

I've tested with these two PSUs:

Seasonic S12G-750 (SSR-750RT Active PFC 3) - The original PSU
Corsair TX850 (CMPSU-850TXV2) - My own spare PSU

I can provide serials too, if necessary!

And it's the same, doesn't work on 780 Ti or 7970, but works with 6850 and 1080 Ti... :S I can usually fix things myself, but this is a mindtwister. 😉

 

[Darkbreeze]

It certainly is. I'm going to look into this to see if I have any ideas myself.