So to clear everything as perfectly as I can I'm going to try to explain to everything that I've done in the past 2 hours to try to fix this with no success. My System before today was a sabertooth P67, i7 2700k and 8gb gskill ripjwasx 1600mhz. And a Asus 7970 + a Gigabyte 7950. Everything worked flawlessly but I decided to upgrade my cpu. So I bought a 4770k, 8Gb of gskill tridentX 2400mhz and a Asus Maximus VI Hero, still keeping both gpu's. After installing everything and powering the pc on I get no video output. Not a problem it sometimes happens, so I try to do the usual, only 1 ram stick only 1 gpu still nothing. At this point my 1 gpu was the 7950 wind force from gigabyte. After a couple of minutes of trial and error I decided to put the 7970 instead of the 7950. SUCESS the system booted perfectly no problem. So I tried to put the 7950 on the respective PCI-express slot (yes it's the correct one I checked the board manual), and after I put the card in connected the power and the crossfire bridge nothing, just a black screen (bear in mind that I still had the DVI cable on the 7970 but after I plugged the 7950 on the other PCI express slot the 7970 no longer could output any video. I though It was kinda strange So I got another power supply and put the old system back together on the table (the sabertooth p67 with 2700k and the old 8gb sticks) I then connected the 7950 there and for my surprise It worked perfectly as it always did. So my question is quite simple...how in hell is this happening? I simply cannot comprehend how the graphics card is working on one board and not working on the other even though the fans speed no video output. I already tried a ton of stuff from BIOS upgrading on the Maximus VI hero, to a fresh windows install (even though that wouldn't make any sense but I was kinda desperate). And another weird thing was that after a while I managed to get the 2 cards working on the new build but instead of displaying image through the boot I would get 10 seconds of black screen and then windows, and both card would be recognised even though I couldn't install the drivers...And if during boot I spammed the delete key to access the BIOS I would get stuck on a black screen and forced to reboot. If anyone could take a wild guess on what all of this could be and how to fix it I would be really really happy because after so much time I have to come to someone to ask for a solution.
I'd say your PSU is probably borked......from what you've described at least.....can u try both PSU's?
Well after reading OP's post again I can't work out what cards went with what PSU's and if they were tested inside or outside the case on what boards. lol so Idk I'm confused now.
The cards were installed in Crossfire in both and old and new motherboards. They work just fine in his old board but the HD7950 won't work at all in his new motherboard. Personally, it sounds like a compatibility issue between the HD7950 and the new motherboard. Since when does a bios flash make a processor compatible with a completely different socket? He went from an LGA1155 processor, to an LGA1150 processor....
I can tell you my 760 didnt boot at all with my mobo, a bios update fixed it so i could boot. It was this experience that told my buddy to do the same thing when it happened on his 280x and it worked for him as well. So since now is when a bios update can fix this problem. What do you have to lose?
OK so I posted my first post and went to sleep to clear my head because after so many hours of trial and error I was getting kinda frustrated. OK so can try to update the motherboard bios but I already upgraded it to a l a newer version then then the one that came with it. I'm starting to think that the VGA bios could be incompatible for some weird reason...but anyways I'm going to upgrade the bios to the latest version and try again but I'm not very confident on it. I'll post an update in a little whille
So I just noticed you have a new motherboard as well. Are you booting in legacy or UEFI mode? Does one of your cards have a Hybrid bios?
Just to clarify once again, I upgraded platform from 1155 to 1150 and changed CPU+Board+Rams. I still have the old P67 System and everything works there without a problem. With the 7950 on the new board I have no video output, nothing so I can't boot in neither Legacy nor UEFI mode. Hybrid Bios?Not really familiar with what that is...
Ok so I'm starting to think that This surely is some sort of incompatibility between the gigabyte 7950 and the motherboard, which in my head makes very little sense...any suggestions on how to proceed to fix this? I really really don't want to switch the board for another one or sell the gpu....
I think you will have to go to UEFI, http://www.techpowerup.com/reviews/ASUS/MAXIMUS_VI_HERO/images/bios_15.jpg advanced menu> advanced tab> PCH settings http://images.hardwarecanucks.com/image/eldonko/MAX6HERO/BIOS/Lbios15.png and System agent menu NB pcie config., http://images.hardwarecanucks.com/image/eldonko/MAX6HERO/BIOS/Lbios17.png both have pcie settings and by one of them try to manually enable pcie gen 2 or 3 for 2nd pcie8x lane. I think this is it http://www.techpowerup.com/reviews/ASUS/MAXIMUS_VI_HERO/images/bios_27.jpg worth a try
Definatly worth the try I'll do it tomorrow morning I'm tired today...trying so many things and none of them working is kinda frustrating. Thanks for the outside of the box idea I'll post back with results tomorrow