Is it possible to fit a 3 slot GPU in a build that only has 2 ...
You know the deal by now; a triple slot GPU will need 3 rear I/O expansion slots in your case, and will fully cover/hover/block/dominate over at least 3 PCIe slots (if your motherboard has 3 PCIe slots all next to each other).
Esonic HM65/HM76 8 slots GPU Mining Motherboard Socket in Pakistan
8 GPU Mining Motherboard – B85 Detailed Description of B85 Motherboard: B85 motherboards are made up specially for mining with 8 pci express slots. You can connect maximum 6 gpu at time for mining ethereum etc.
ZEBRONICS ZEB-H61M2 with PCIE M.2 / NVMe Slot (LGA 1155 Socket ...
Multi-GPU may or may not be possible depending on the availability and layout of other PCI Express slots on a Micro ATX motherboard.
Motherboard RAM Slots: What They Are and How to Use ...
FRONTECH H61 Chipset Motherboard with 2xDDR3 RAM Slots LGA1155 Supports i3/i5/i7/Pentium Processors | 6+4 USB Ports | 4xSATA Slots | NVME Slots, 1xPCIEX16, 1xHDMI, 1xVGA (FT-0470).