Configuration
Graphics preset
high
Screen refresh rate
90fps
Framerate limit
none
Average framerate
45fps
Tdp limit
12w
resolution
1152
x
720
System
Proton version
9.0-3
Steamos version
3.6
Note
Highly recommend installing FusionFix, adds AA, allows to tweak motion-blur & DoF settings and many more fixes to the historically terrible game port. "Fixing GTA IV with 4 Mods" by TJGM on Youtube goes in depth on the benefits and install guide, just requires this launch option for it to work on the Deck, " WINEDLLOVERRIDES="dinput8=n,b" %command% ".
A small visual comparison between modded and default: https://imgsli.com/MzU4OTE3
I prefer the look of FSR especially with SMAA enabled over upscaling to 1920x1200, slightly better performance and better battery life, but it's also personal preference.
Loading screens on a Sandisk Extreme Pro are the same speed as on the stock 512gb SSD, ~15seconds to get in to game after launching.
Power Draw bounces around 15-19.5W depending on Area, and crossing the big bridges usually gives ~30ms frametime spikes no matter the graphical settings, but other than that it's perfectly playable and imo is the Superior Vanilla experience.
Display Settings -
Motion Blur: Off
Bloom: On
Console Gamma: On
Screen Filter: Off
Depth of Field: High
Tree Lighting: PC+
Tree Alpha: PC
Definition: On
Graphics Settings -
Texture Quality: High
Reflection Resolution: High
Water Quality: High
Shadow Quality: Medium
Night Shadows: Medium
Texture Filter Quality: Anisotropic x16
View & Detail Distance: 75
Vehicle Density: 70
Vsync: Off
Shadow Filter: Sharp
Sun Shafts: On
Anti-Aliasing: SMAA
Lamppost Shadows: Off (While this does look better in some places, it completely bugs out the lighting in certain other places.)

Sears Tower
(1 report)
Does not own this game through Steam