"It shouldn't be unusable, just slow using the x4 slot. If that's the case, either live with one card or replace the MB with one that is X8, X8 or better."
Thanks for the reply and yes that's exactly what I would have expected. The physics for managing 3d and sli stubbornly remains greyed out. Innaccessable. I have repeatedly flashed Cmos jumpers before each boot. Tried the cards in alternate slots. I can get slower speeds but they remain mismatched (16/1, 16/4, 8/1, 4/1 etc.). I suspect that Gigabyte might well be aware of it too. If the stony silence on the topic of "advanced chipset features."
Miktha . . .