In my quest for playing games I have converted my Intel iMac into a gaming machine running latest Windows 11 without a TPM chip! I downgraded OCLP patched macOS Sonoma to Ventura which is the last version officially supported by Apple on my 2017 iMac with the hope that I can play many Windows games on VMWare which runs Crysis 3 without any issues, which I wrote about before. I am able to play Crisis Core -Final Fantasy VII- Reunion in moderate settings with some lag in VMWare. But trying Final Fantasy XIII crashes the VM every single time. So I had decided to clean install Windows 11. Below are the steps followed.

Clean Install of Windows 11

Before deleting all data on the iMac, we need to get a wired internet connection as Wi-Fi won't work without installing drivers during setup process and now we need an internet connection for installing Windows. Along with wired keyboard and mouse. The below method doesn't require to have a TPM chip. That check will disabled manually during the install process.

  1. Download latest version of Windows 11 iso. The version I installed is Win11_24H2_English_x64.iso. This version has tabs for the Explorer which is a must for using any OS these days.
  2. Format USB drive as exFAT with MBR partition scheme.
  3. Copy the contents of the iso file to the root of the USB drive.
  4. Copy the Apple Windows 10 drivers specific to your system on to the USB drive in a separate folder.
  5. Connect ethernet cable to the iMac and the router with a working internet connection.
  6. Reboot the system and press and hold Alt/Option key during boot process to show the boot menu. Select the EFI boot option and proceeed.
  7. When the installation shows the first input screen which is the country selection, press Shift + F10 to bring the command prompt.
  8. Type regedit to launch the Registry Editor.
  9. Create a new key LabConfig under HKEY_LOCAL_MACHINE\System\Setup folder with three DWORD32 bit value BypassTPMCheck, BypassRAMCheck, BypassSecureBootCheck with hex value of 1. Close the registry editor and the command prompt and proceed with the installation. This will allow installation of Windows 11 without TPM chip.
  10. Delete all partitions and create a primary partition of say 512 GB, select and proceed with the installation. We need to sign in to a Microsoft account for the user account option. I did not find a way to bypass this. Keep this administrator account and create a standard user local account later for daily use.
  11. After Windows installation, install the iMac drivers from the setup. Ignore the driver verification failed warning and proceed because we are installing Windows 10 driver. There is no Windows 11 driver from Apple.
  12. I faced issue with sound not working. I installed Cirrus driver manually but did not work. I however got it working later after trying many things. In Device Manager, first right click on the system name and choose Add drivers and point to the root directory of the Apple Windows 10 drivers. Install all the drivers from the $WinPEDriver$ .inf files. I am not sure if this step is required. Then uninstall all sound drivers under Audio inputs and outputs, Sound, video and game controllers. Windows will automatically install them back and this time the sound worked. That's it. There is no sound going mute on reboot like Windows 10. Everything else works fine.

With this I am able to play games at 5K resolution of 5120 x 2880 px without any stutter. Since I develop for iOS and I don't want to run patched OS, I am unable to install Xcode 16 which has Swift Testing framework integration. Eventually I can no longer use this iMac with macOS Ventura to submit apps to the App Store making it completely obsolete for iOS development. Eventually I have to upgrade my mac. With this setup I have a nice gaming rig making efficient use of outdated iMac.

Update on Sat, 27 Dec 25: I don't use this setup. I installed macOS long time back as I wasn't playing any games much.