I tested both resolutions in my setup and found that there was a lot more noticeable jerkiness in the video when using 1920x1080.
If you want to watch 1080p content such as Blu-ray discs from your laptop, then you can change the adapter's resolution through Windows.
The resolution on my laptop was kept native, while the WiDi adapter used 1280x720. I set up the ScreenCast TV as a secondary display, which allowed me to watch video on TV while still being able to use the laptop to browse the Web and type up documents and edit photos on its main screen. The signal quality and strength was excellent in this setup and it represents an optimal situation. I tested in a close-proximity environment with the adapter located about three metres away from my test laptop. That said, I found the performance of the Belkin adapter to be quite good. If you use the Internet heavily while also using WiDi, you might experience a noticeable performance hit to the video quality on the screen as your laptop's wireless adapter works to stream the video as well as handle all your Internet traffic. You don't need to be connected to a wireless router in order for WiDi to work the connection is made between your wireless adapter and the Belkin WiDi adapter directly.
In my tests using a Samsung Series 6 LCD TV, the Belkin filled the screen with my laptop's output perfectly. The mouse pointer can be hidden from view if you only want to use WiDi as a presentation tool, and the screen's edges can be adjusted if they fall from view on your screen or if they don't fill it completely.
If you exit the application, your connection will be lost. To use WiDi, its application will need to run in the background while you are connected. You will need to enter a PIN that the Belkin will show you on the screen, and that's a one-time deal subsequent connections won't require you to enter a PIN, unless you use a different laptop. If you do, simply launch it, do a scan for the adapter, and connect to it.
On the laptop, you will need to make sure that you have the latest version of Intel's WiDi software installed. Simply connect the adapter to your TV using either HDMI or a Composite connection, and switch your display to that input. The Belkin ScreenCast TV doesn't take a lot of expertise to set up. Shortcut keys to perform this task will also be shown in the WiDi software. Using Windows 7's Display Properties, you can set the ScreenCast TV adapter to be an extended display, which will allow you to use a maximum resolution of 1920x1080. In its most basic form, the Belkin ScreenCast TV duplicates your laptop screen exactly - in my tests, it used a default resolution of 1280x720. The main purpose of the Belkin ScreenCast TV is to make it easy to throw content up on your TV (or other big-screen device), without having to fiddle with cables or excessive configuration settings on your laptop.