Performance

Run IW4x with the high performance GPU

One of the most common causes of bad performance is the game running against the integrated GPU instead of the dedicated GPU in a system that has both.

In order to solve this, you can configure the IW4x application to run against the high performance GPU with the steps below, depending on the operating system you are using:

Windows

1. Navigate to Display > Graphics settings > Graphics performance preference in your Windows Settings.
2. If you have the option to select specific apps in the graphics settings, set the IW4x app to use the high performance GPU.

If you have an Nvidia GPU, this can be applied via the Nvidia Control Panel:

1. Navigate to 3D settings in the Nvidia Control Panel app.
2. Choose select a specific program and set the IW4x app to use your high performance GPU.

Thanks to @joel_rpc for outlining these steps.

Linux MESA (AMD or Intel graphics cards)

The environment variable MESA_VK_DEVICE_SELECT_FORCE_DEFAULT_DEVICE=<ID> should be applied if using Mesa drivers to tell the game what graphics card it should use, where <ID> is the identifier number of the graphics card you wish to use.

In order to get the ID numbers of your graphics cards, you may run vulkaninfo --summary and look for the Devices: section of this output. An example of this output may be:

Devices:
========
GPU0:
  apiVersion         = 1.4.311
  driverVersion      = 25.1.9
  vendorID           = 0x0000
  deviceID           = 0x0000
  deviceType         = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
  deviceName         = AMD Radeon RX 6900 XT (RADV NAVI21) # This is the important part.
  ...
GPU1:
    ...
    deviceName         = <the wrong graphics card> # We likely do not want to use this one.
    ...

In which case, the desired GPU would have an <ID> of 0.

If you do not have the command vulkaninfo, please consult your Linux distributions documentation on Vulkan tools.

If you wish to apply this via Steam, such as in the case you are launching IW4x as a non-Steam game, you may follow these steps:

1. Right click on your IW4x non-Steam game entry in your Steam library.
2. Left click on Properties.
3. Add MESA_VK_DEVICE_SELECT_FORCE_DEFAULT_DEVICE=<ID> %command% to the Launch Options section, where <ID> is the ID number gathered above.

Linux Nvidia

The environment variables __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia should be applied to tell the game to use the Nvidia graphics card.

If you wish to apply this via Steam, such as in the case you are launching IW4x as a non-Steam game, you may follow these steps:

1. Right click on your IW4x non-Steam game entry in your Steam library.
2. Left click on Properties.
3. Add __NV_PRIME_RENDER_OFFLOAD=1 __GLX_VENDOR_LIBRARY_NAME=nvidia %command% to the Launch Options section.

If your distribution has documentation around Nvidia Optimus, you may consult that as well.

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DXVK

DXVK is a translation layer for Direct3D -> Vulkan, and can be particularly useful on Intel ARC graphics cards if you are facing issues.

Additionally, in some cases, DXVK can grant better performance and lessen stutters, and can be enabled via the IW4x launcher.

Note

The following instructions assume you have already run the IW4x launcher at least once.

Installing DXVK

Once you’ve installed IW4x, you should see the following folder and files in your game directory:

• DirectoryCall of Duty: Modern Warfare 2

  • Directoryiw4x/

    • …
  • Directorylauncher

    • cache.json
    • config.json
    • log.log
  • iw4x.exe
  • iw4x-launcher.exe
  • … other files and folders

If you open config.json in a text editor (such as Notepad), you’ll see something like this:

launcher/config.json

{
  "update_only": false,
  "skip_self_update": false,
  "force_update": false,
  "args": "-stdout",
  "offline": false,
  "testing": false,
  "disable_art": false,
  "dxvk": false
}

The important option here is "dxvk": false. Change the false after "dxvk": to true, and then run the launcher.

Uninstalling DXVK

If you would like to uninstall DXVK, repeat the same steps as in Installing DXVK above, but changing "dxvk": back to false.

After doing this, delete the d3d9.dll file from the game folder.