When running on a wired Ethernet connection, Stadia just about performed as advertised. That means smooth frame rates that generally held at 60fps and controls that felt largely indistinguishable from those on local hardware (even with the Stadia controller connected directly to the router via Wi-Fi). While there was likely
some additional input lag over local play, in Ethernet tests it wasn't enough to be noticeable to the naked eye, even for twitchy shooters and fighting games. Playing with friends online was similarly smooth, with no significant lag over a wired connection (though we weren't able to test out online voice communications during the pre-release review period).
The stability of wired Stadia play was in stark contrast to the Wi-Fi Stadia experience, which was inconsistent to the point of aggravation. This became apparent in our very first tests, playing
Mortal Kombat 11 on a Chromecast Ultra stationed on a TV one floor above the router.
The first few single-player matches played beautifully, with crisp, smooth graphics and controls that made quick special moves easy to pull off. Then the Chromecast suddenly warned me that my connection had become "unreliable" and that "gameplay may stop" if it didn't improve. The sudden message was all the more vexing because I was alone in the house, with no other devices actively running on the network.
At that point, I faced a noticeable drop in resolution and frequent frame-rate stutters that made the game nearly unplayable. As promised, gameplay was forced to stop a couple of times as Stadia kicked me back to the main menu (while I was able to reconnect relatively quickly and without losing my spot in the game, but it was still a major annoyance).
