“After dozens of hours on just Steam Deck, Starfield feels good in some parts, but really struggles in the bigger cities. Turning everything to low and enabling FSR2 is basically the only way to play it right now on Valve’s handheld, and even that drops to 20fps often in the first major city (New Atlantis). The game itself can look very good on the device screen in many parts, but it is very CPU-heavy right now. This has been tested after the day one patch as well.”
It makes a ton of sense: the Steam Deck is memory bandwidth limited.
You can overclock the CPU and you get a few FPS extra on some games. You overclock the memory (which only works in models with non-Samsung memory) and the performance gains can be in the neighborhood of 10 to 15 FPS.
Though the GPU is for sure a big limitation, it could offer way more consistency if paired with even faster memory. Cities and other areas filled with multiple moving models are perfect scenarios to demonstrate memory pressure.
One tiny way one can help is reducing or outright disabling anisotropic filtering. We take it for granted on desktop CPUs, we can push it to 16x and not notice a single FPS drop - however, it’s extremely reliant on memory bandwidth so on a device like the Steam Deck forcing it off can help tremendously with 1% lows.