Hi hermit_panda,
I don't fully understand what your problem is, Are you getting no output to your monitor or is it that you can't configure SLI as you wish?
As I understand it and these are only my opinions.
Moving from 16x to 8x causes either very small or no performance drop since current bandwidth utilization is not saturated even with the most powerful cards and the two slots will most likely both run at x8 anyway.
The PCIEX8_1 and PCIEX8_2 slots share bandwidth with the PCIEX16_1 and PCIEX16_2 slots espectively. When PCIEX8_1 is used, the PCIEX16_1 slot will operate at up to x8 mode; when PCIEX8_2 is used, the PC IEX16_2 slot will operate at up to x8 mode)
Maybe someone will come on with better SLI experience once they know the real issue,and I can understand your frustration as those are quite bulky cards.
Please also let us know you PSU?
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