How thunderbolt 3 USB-C is able to provide 40 Gbit/s ?

[Windows Central Question]

the maximum speed of thunderbolt 3 protocol is 40 Gbit/s, the connectivity behind that USB-C port is four lanes of PCI Express Gen 3
the maximum speed of it is 32 Gbps , so the question is how thunderbolt 3 is able to provide throughput that exceed the Computer bus (four lanes of PCI Express Gen 3) ?

 

[Ryujingt3]

the maximum speed of thunderbolt 3 protocol is 40 Gbit/s, the connectivity behind that USB-C port is four lanes of PCI Express Gen 3
the maximum speed of it is 32 Gbps , so the question is how thunderbolt 3 is able to provide throughput that exceed the Computer bus (four lanes of PCI Express Gen 3) ?

This should help explain it:

https://blog.macsales.com/37294-tech-101-what-thunderbolt-3-speeds-and-capabilities-mean-for-you