What is the Difference Between PCIe Gen 3 & Gen 4?

What is the difference between PCIe Gen 3 and PCIe Gen 4? will gen 4 ssd work in gen 3 slot BUT you go buy the off brand no name cheaper 1TB Gen 4 NVME for lets say, 70$ (6-7K read william hill slot tournaments will work on the Intel Evo platform with 12th Gen Intel Core i7 processors They will all come with LPDDR5 RAM and NVMe Gen 4 SSD storage

willy wonka slot machine for sale If your motherboard has a slot you are usually good to go You can use a SSD for both boot and storage If not, you can still use a NVME