Run a large-enough WiFi network and there's bound to be that one device that can't quite hold on to a fast connection, like the tablet in your bedroom or a laptop in the backyard. But how do you quantify that flaky connection? Google can help. It's deploying an updated Network Check feature for Google WiFi routers that will check the performance of devices on your network and help you identify ones with unusually low performance. You'll know if you need to move an access point, move a device or (if it's truly bad) expand your network to provide better coverage.