Whether you can use an IPG will depend on how serious a gamer you are. A dGPU is required if it’s the demanding FPS type.
Wake from S3 is a function of the driver, so it’s up to USB-UIRT to support it or not. The motherboard shouldn’t play a role unless it was truely ancient and didn’t provide power to USB devices in standby.
What is your budget? Unless it’s really limited a Haswell i5 (which gives you the option to try the IPG) w/ 8GB DDR-1600, 120GB SSD, etc is a good starting place.
