Q: Why do I see SR-IOV as an option in my virtual machine configuration, when my machine doesn't support SR-IOV?

A: The option to enable SR-IOV is always available as part of the Hardware Acceleration option of the Network Adapter, which the screen shot shows. To learn more about SR-IOV, see my FAQ "What is SR-IOV?"

SR-IOV Network Adapter Hardware Acceleration Option

Basically, setting the option tells Hyper-V to use SR-IOV if SR-IOV is available. It's not guaranteeing the availability of SR-IOV.