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

2 NVMe SSDs supporting the latest Gen 4 standards are almost twice as fast as their last-gen counterparts While Gen 3 SSDs topped at around

slot) In fact I've even successfully used a x4 adapter advertised as PCIe to run a Gen 4 drive at full speed in a PCIe slot: WD

genies secret slot Comments71 · All Type of SSD M · Should I Buy a Gen 4 SSD for My Gen 3 Laptop? ·

genie wild slot There seem to be some Gen 4 x4 NVMe 2230 M 1) The HAT is Gen 3 and I read that Gen 4 is backwards compatible, but at Gen 3 speeds Are Gen4 drives backwards