Hi everyone,
I'm struggling getting my x6 HD7950 mining rig alive,

Rig:
x1 G1610
x1 MSI Z77A-GD65 GAMING
x2 CORSAIR DDR3 4GB
x4 HD7950 VTX + x2 HD7950 SAPPHIRE DUAL-X
x1 VGA Screen with VGA-DVI adaptor
x1 LEPA 1600w
System: Xubuntu 13.10 amd x64 desktop
All the 12v rails are connected and I have seperated all the gpus into 3 different cables. (2x3 12v rails "or pci-e riser's molex whatever")


---XUBUNTU---

Method:
I've installed Xubuntu with only one gpu (impossible with more than one to proceed the installation),
I could access the desktop without any issue at this moment,
then I've typed the following lines:
sudo apt-get install fglrx-updates fglrx-amdcccle-updates fglrx-updates-dev
sudo aticonfig --lsa
sudo aticonfig --adapter=all --initial
sudo shutdown

I've then tried to plug my 6 gpus during the shutdown (as I do usually with other rigs), but after the reboot, sometimes I can see the xubuntu logo logging in, sometimes not but that's not the problem, the problem is that the screen turns off (black screen) just after the logo but everything seems to work fine (by typing the Verr num key to check if the system is still alive), I've tried to plug the screen on all the gpus but still a black screen, no answer.
I've tried to reboot with one gpu and it didn't work too! I wanted to know if amd have updated their drivers soon because it worked before with the exact same method. I wonder where this can come from, maybe the 2 different brands of my gpus? Maybe Xubuntu has updated something? Or my last idea is maybe my dvi-vga cause the problem but it's the exact same screen that i used before when it worked.

I'm stuck on this since 3 days now.


---WINDOWS 8.1---

Yesterday, I've installed Windows to check if it goes better, but I have another problem there, 5 out of 6 gpus have seen their respective drivers installed, (latest catalyst 13.12), it's impossible to install the same driver for this last gpu so I've installed Catalyst 12.6 (from one tutorial advised by GoBitGo), I was then happy to see my 6 gpus recognised but after having launched cgminer 3.7.2, it keeps on closing itself after 1 second. Then I've reinstalled amd catalyst 13.12 over everything and the 6 gpus were still recognised, cgminer worked ! But the issue was that 6 gpus were mining at 600 KHs each, and the GPU0 was mining at 50 KHs maximum.


Best Regards and thanks for your help,