I have a modem which also functions as a wireless router which is supplied by my internet company. The lan ports on it are only 100 megabits, but my new wired network will be cat6 which allows 1000mbs. If all my computers are plugged into a switch which allows 1000mbs and the wireless router is plugged into the switch, will the wired computers have a connection speed to my server of 1000mbs or 100mbs? The server too will be connected to the switch.
Your devices connected to the switch will all operate at 1 GBps. All devices on the network will be able to communicate with your router/modem at 100MBps. If your wireless router/modem is an 802.11n device, this would limit throughput to 100MBps to your wireless devices.