Only the x16 slot is PCIe 2.0. The other 2 PCIe slots are 1.x
It may sound daft, but it's not unusual. Mostly depends on the motherboard chipset. The 2.0 slots are usually reserved for graphics cards which can require enourmous bandwidth.
Galaxy Note 8 vs iPhone X
Graphic tees: 14 best websites to find your next T-shirt
How to update iOS on iPhone or iPad
Les meilleures applications pour enfants 2017