Earlier versions of MW3 (2011) were optimized for Windows 7; running these on Windows 10/11 can "cripple" performance due to how the newer OS handles full-screen optimizations.

feeling like a personal insult. Every slide-cancel felt sluggish, and his kill-cam was a stuttering mess. He wasn't playing on a toaster; he had a "beast of a rig," yet the frame rate refused to budge, as if his PC had decided 45 was the speed limit for life.

The game may default to a low number of CPU cores, causing a bottleneck that limits FPS.

A prevalent anomaly reported by the player base of Call of Duty: Modern Warfare III involves the game engine rigidly capping the frame rate at approximately 45 Frames Per Second (FPS), despite hardware capabilities supporting significantly higher outputs. This white paper identifies the root cause as a conflict between the game's internal Vertical Synchronization (V-Sync) logic and the Windows Desktop Window Manager (DWM) when the application is running in "Borderless Windowed" mode. This document outlines the step-by-step mitigation strategy to restore unlocked frame rates.

(For AMD/Intel GPUs with broken OpenGL fallbacks) Download dxvk-2.x.tar.gz → place d3d9.dll + dxgi.dll next to .exe . This replaces DirectX 9 calls with Vulkan, often removing 45 FPS lock.

Note: You may need to navigate menus slowly due to the low framerate.