If it was network lag you would notice everything else lagging as well. It sounds like input lag which could be caused by memory, bad drivers, bad ports, bad cable, etc.

A few things you can try;
- Reset the controller, the tiny hole on the back.

- Unplug the controller, open up device manager, go to View and check show hidden devices and remove all of the HID-compliant game controllers under Human Interface Devices and xbox 360 controller for windows under Xbox 360 Peripherals. Reconnect controller and let it install.

- Roll back your drivers / check for updates / re-install drivers.

- use a 2.0 USB port, they are colored black (3.0 are blue)

- Replace the cable.

- Buy a DS4 and use Input mapper.