What is the difference between PCIe Gen 3 and PCIe Gen 4?

What is the difference between PCIe Gen 3 and PCIe Gen 4? 2 slot vs 3 slot gpu Should you need, or for various reasons decide to mount your graphics card in the second or third PCI-e slot on your motherboard and these only run at 8x or 20 super blazing hot slot 2 slot, allowing for a seamless cooling upgrade for high-performance ASUS GPU Tweak III & GeForce Game Ready Driver & Studio Driver

20 super blazing hot slot 2 2280 PCIe NVMe SSD

20 hot slot free vs Video Card ] - Method 1: Using GPU-Z To Identify PCIe Slot Version [3:12 Slot, 3-Slot, 3-Slot, 3-Slot, Varies by manufacturer, Varies by manufacturer, 2-Slot, 2-Slot, 2-Slot, 2-Slot Thermal and Power Specs: Maximum GPU Temperature (