How do single slot and dual slot graphic cards differ?

GPU max power4, GPU max length GPU ports IO ports bandwidth5, USB-C ports6 & ctrl PCIe to to TB3 encoder7 slots @width, Updated

That makes these a poor choice for use in multi-GPU systems In those cases, a Slot Width, 2 Outputs Port 1, HDMI Port 2, DisplayPort Port 3

gpu expansion slot Image from NVIDIA The main considerations when buying a GPU are: memory ; performance ; slot width

gpu blocking pcie slot GPU GeForce RTX™ 4090; GeForce RTX™ 4080 SUPER; GeForce RTX™ 4080; GeForce 2-slot width; Overclocking; Zero Frozr; TORX Fan; Backplate; TORX Fan