Does Ethernet affect disc game download speeds?

If you mean Ethernet compared to wireless then I would say it should. Using a hardwired connection (such as Ethernet) would ensure a solid connection to the internet (provided the entire connection route is hardwired). The connection speed would only then be capped or have issues if there are any issues on the network.

Wireless can be just as good, provided you have a fantastic connection. Otherwise you're dealing with other wireless interference issues, possible antenna issues, as well as other wireless traffic (possibly from other devices not even on the network).

If possible always use a hardwired connection. While I'm certain at some point the technology for wireless will make it stable enough to rivial hardwired connections, it's not there yet.

/r/PS4 Thread