StarCraft II: Best Variables.txt for Zero Input Delay

The objective is to minimize the Flip Model latency and ensure the mouse cursor ($C_{mouse}$) is decoupled from any post-processing or V-Sync buffers.

File Path & Setup

1. Navigate to: C:\Users\[YourName]\Documents\StarCraft II\Variables.txt
2. Backup: Copy the original file before editing.
3. Pro Tip: In 2026, many competitive players use DXVK (Vulkan wrapper) for SC2. If you are using it, ensure your dxvk.conf matches the Variables.txt settings for maxFrameLatency.

Optimized “Low-Latency” Configuration Table

Parameter	Recommended Value	Technical Purpose
frameratecap	240 (or Monitor Hz)	Prevents the CPU from “over-queuing” frames it can’t render.
reduceMouseLag	1	The Core Fix. Forces the game to use a high-priority mouse thread.
vsync	0	Disables the engine’s internal synchronization buffer.
mouse_acceleration	0	Disables software-level cursor scaling for raw input.
bitrate	16	Reduces the data overhead of UI and audio assets.

HowTo: Engineering the Zero Delay Pipeline

Follow these GameEngineer.net technical steps to optimize your command response:

1. The “Reduce Mouse Lag” Flag: In the Variables.txt, ensure reduceMouseLag=1 is set. While this is available in the menu, the file override ensures the m_rawinput equivalent is forced at the engine level, bypassing Windows’ $M_{accel}$ entirely.
2. Hard Capping the Frame Rate: Set frameratecap=240 (or whatever matches your monitor). If the game runs at “Infinite” FPS, the CPU becomes overwhelmed with the simulation of 200+ units, causing a “input hitch” ($S_{hitch}$). Capping it provides the CPU with the overhead needed to process clicks immediately.
3. Eliminating the Render Buffer: Add or change maxFrameLatency=1. This tells the DirectX/Vulkan driver to only hold one frame in the queue. While this may slightly lower your maximum FPS, it drastically reduces the time between a click and the visual confirmation of that action.
4. Disabling “Physics Stutter”: Set physics=0 or 1. In large battles, the Havok physics engine can stall the main game thread. By lowering this, you ensure the “Command Thread” stays active even during 400-unit Zerg vs. Terran engagements.
5. Exclusive Fullscreen Protocol: Ensure windowmode=0 (Exclusive Fullscreen). Although Windowed-Fullscreen is faster for Alt-Tabbing, it introduces DWM (Desktop Window Manager) latency, adding roughly ~10ms of delay ($L_{DWM}$) that is unacceptable for high-level competitive play.

// SC2 Zero-Delay Config
frameratecap=240
frameratecapGlue=60
reduceMouseLag=1
vsync=0
mouse_acceleration=0
bitrate=16
maxFrameLatency=1
shadows=0
lighting=0
softparticles=0

Technical Explanation: Tick Rate vs. Input Frequency ($I_{freq}$)

StarCraft II’s logic runs on a Tick Rate ($T_r$) that is independent of your FPS. On “Faster” game speed, the game updates its state 22.4 times per second.

$$Input\_Latency = \frac{1}{FPS} + \frac{1}{Tick\_Rate} + L_{hardware}$$

By engineering the Variables.txt to use maxFrameLatency=1 and reduceMouseLag=1, we minimize the $1/FPS$ component and hardware buffer. This allows your input to be registered in the very next game tick ($T_{next}$), providing the “snappiness” required for precise marine splits or blink-stalker micro.