Question about home networking

[Robert Seltman]

I have both ethernet direct into my upstairs iMac as well as my Apple WiFi connected to the same iMac. Both are from the same internet-cable service coming into my home. How does my iMac know which to use? Is there a speed difference between direct ethernet verses WiFi from the same service (Should I turn off the WiFi on the iMac?).

My primary reason for having WiFi is for the computer downstairs in the kitchen. Will my turning off the Wifi in my upstairs computer in any way effect the speed or connect-ability of the downstairs computer? I ask this only because I think of my upstairs computer as my administrative hub, this may not necessarily be the case, I just do not have a clear mental picture of how home networking works.

[Col]

Ethernet (1,000 megabits/sec) is considerably faster than even IEEE 802.11n WiFi (absolute maximum of 600 megabits/sec), so if a computer is connected to both, it will use Ethernet in preference to WiFi. So there is no need to turn WiFi off.

I understand that if computers with older WiFi protocols (IEEE 802.llb or IEEE 802.l1g) connect to the WiFi network, then all devices in the network connect using that older, slower protocol, so it would be particularly useful to use Ethernet with the older devices.