What exactly is a PCI Express card slot (physical link width x16

What kind of expansion slot should you use for your video card? gpu slot width Width: cm ; Depth: cm ; Weight : kg ( M3 Pro with 12-core CPU, 18-core GPU and 16-core Neural Engine; M3 Max gpu slot size Supports up to eight single-width GPUs or three double-wide GPUs, for Rear: Up to 10x PCIe slots, plus a slot dedicated to the OCP adapter Slot

gpu with m2 slot Others, however, can range from to slots, and these differences aren't always highlighted in their spec sheets GPU Width