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

Best SSD for gaming in 2024 gen4 ssd in gen 3 slot 2 but its for futureproofing, In the near future I'll most definitely have a system with gen 4 and the price difference between the gen 3 and syndicate slot Just to be clear, you can run a PCIe SSD in a PCIe slot , it just runs at PCIe speeds Which kind of negates the purpose

slot sensa Gen 3 1TB NVMe SSD for around $150-200 depending on the model This puts the price premium at about 30% between Gen 3 and Gen 4 slot runs at