m_rawinput and Fixing Mouse Acceleration

Consistent aim depends on one thing above all: the same physical mouse movement must always produce the same in-game turn. Mouse acceleration breaks that — move faster and you turn further than the distance alone would suggest, so you can never build reliable muscle memory. CS 1.6 gives you m_rawinput to bypass acceleration entirely, plus a set of legacy launch options for the same purpose. This explains what each does and how they interact.

1. What acceleration actually is

Mouse acceleration means the cursor's on-screen movement depends on how fast you move the mouse, not just how far. Windows applies this through the "Enhance pointer precision" option, and older games applied their own on top. For desktop use it feels natural; for aiming it is poison, because the same 5 cm swipe turns a different amount depending on speed. The goal is a flat 1:1 relationship: distance in, distance out, every time.

2. Enable raw input

The cleanest fix is raw input, which reads the mouse hardware directly and ignores the entire Windows pointer pipeline including acceleration:

m_rawinput 1

With this on, "Enhance pointer precision" and the Windows pointer speed slider no longer affect the game at all — the engine takes the raw counts from the sensor. This is the single most important aim setting, and on modern systems it is the recommended approach over the legacy options below. Save it to your config.cfg.

3. The legacy -noforce launch options

Before raw input, players forced the engine to stop applying its own acceleration and to stop overriding Windows mouse parameters, using three launch options:

-noforcemparms -noforcemaccel -noforcemspd

• -noforcemparms — do not force custom mouse parameters; use the Windows ones as-is.
• -noforcemaccel — do not force mouse acceleration.
• -noforcemspd — do not force mouse speed.

Add them in Steam > Properties > Launch Options. With raw input on these are largely redundant, but they do no harm and are a sensible belt-and-braces measure. See the launch options guide for how they sit alongside your other flags.

4. Turn off acceleration in Windows too

Even with raw input protecting the game, disable Windows acceleration globally so every application and the desktop behave predictably. Open Settings > Bluetooth & devices > Mouse > Additional mouse settings > Pointer Options and uncheck Enhance pointer precision. Set the pointer speed slider to the exact middle (the 6th of 11 notches), which is the only 1:1 position — any other notch scales your counts up or down.

5. Set sensitivity on a clean base

Once the input path is flat, sensitivity is a pure multiplier you can trust. Set it in the console:

sensitivity 2.0

Do not use the in-engine m_customaccel acceleration natives — they reintroduce exactly what you just removed. Leave any custom acceleration off:

m_customaccel 0

With acceleration gone, your sensitivity and DPI together define a fixed cm/360 (centimeters of mouse movement for a full turn), and that number stays constant, which is the whole point.

Common errors

• Aim still feels floaty with raw input on — the mouse's own driver software is applying acceleration or angle snapping. Turn those off in the vendor software.
• Sensitivity changed after enabling raw input — expected. Raw input removes Windows scaling, so your effective sensitivity shifts; re-tune it once and it stays put.
• m_rawinput does nothing — it did not save. Add it to config.cfg; a console-only change reverts next launch.
• Cursor speed differs between desktop and game — that is normal and fine. Raw input deliberately decouples them; only the in-game feel matters.
• Turns are inconsistent at the same sensitivity — m_customaccel is on, or Windows Enhance pointer precision is still checked. Disable both.

Verification

The definitive test is a repeatable swipe. Put a small mark on your mousepad, aim at a fixed point on a wall in-game, and swipe the mouse from the mark to the same end point at two very different speeds — slow and fast. With acceleration gone, both swipes must land the crosshair on the same spot. If the fast swipe overshoots, acceleration is still active somewhere: recheck m_rawinput 1, Enhance pointer precision, and your mouse software. Once slow and fast land identically, your aim is 1:1 and every hour of practice now compounds instead of fighting a moving target. It is worth doing this test again after any Windows update or mouse-driver reinstall, since those occasionally re-enable Enhance pointer precision behind your back. Pair this with the wider input lag fixes so the clean input path is not undone by a frame cap or v-sync sitting on top of it.