Google Stadia: latency analysis - re-testing Assassin's Creed Odyssey
But what about the games? Assassin's Creed Odyssey took point in the Project Stream demo and it's still Google's 'hero' game. In our prior testing of Assassin's Creed Odyssey on Project Stream, tested on a home internet connection, we pegged button-to-pixel latency for the system at 179ms. The game - which we now know to be a full port of the main line console version of the game - operates at 1080p at 30fps, the half-refresh frame-rate adding to the overall lag. Our measurement here was using a LAN connection to the router, with 200mbps of bandwidth.
I had the opportunity to re-test the system using a later version of the streamer, playing the game on a Google Pixelbook, running ChromeOS and connected via WiFi. The chances are that the internet connection here is even more capable than the 200mbps connection we used previously, but despite the fact that we used WiFi (which adds anything up to 10ms of lag in our previous tests, though router and device configuration could change that) and that we don't know the display lag of the Pixelbook, our most consistent button-to-pixel result is 166ms. Google also offers developers a 'worst case scenario' mode to allow for testing in adverse conditions, which simulates a poor, noisy 15mbps DSL connection.
As the tests are comparing data that's not fully like for like, I wanted to demonstrate the range of latencies you could encounter, so on the second row of the table, I've added back in the complete end-to-end totals for the local experience. The LG C8 we used adds 21ms of lag in Game Mode.
pixelbook
We used a Pixelbook for playing AC Odyssey, recording latency between button-press and response with a 240fps high-speed camera.
Google Stadia* Google Stadia 15mbps** Project Stream PC 30fps PC 60fps Xbox One X
Latency 166ms* 188ms* 179ms 112ms 79ms 145ms
Latency (inc display lag)*** 166ms 188ms 200ms 133ms 100ms 166ms
* The Stadia tests were carried out on a Google connection vs our Stream tests 'in the wild' on a 200mbps connection. However, the Stadia tests include display latency on a Pixelbook (which we cannot measure) and were also carried out via WiFi networking. Both of these factors will add additional latency, while our Stream demo tests were carried out via a LAN hook-up to the router.
** The '15mbps' mode is a simulation mode offered to developers, designed to mimic response on unstable connections. Image streaming takes a hit also, in terms of both resolution (1080p becomes 720p) and quality.
*** This comparison stacks up overall measured latency end-to-end, with the local machines running on an LG C8 OLED display with game mode enabled, adding 21ms of lag. The Pixelbook display's latency is unknown.
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