Three questions:
1. Did you still get boot chimes for every variation of RAM swaps you did?
2. Did you still get boot chimes with every GPU you tried?
3. PCI slots 1 and 2 are x16 and 3 and 4 are x4. Did you try a GPU in a different slot?
Maybe the bottom PCIe slot is damaged?
Yes to all of those. Always chimes, never displays. We tried 3 different cards in every slot. Moved ram around too. I had a light on one ram stick so I eliminated that one. But I still had 2 sticks in each board, in the first 2 slots. A thing too is, the fan on the original card went to 100% immediately, the other 2 cards has no fan. Is there something on the motherboard that measures thw temperature? Maybe it thinks all the cards are overheating and doesn't mKe them display?