Enhance Lightroom performance with Retpoline fix

As usual, many users complain about Adobe Lightroom Classic CC performance. In part, this is Adobe’s fault, but on older computers, this is also caused by the notorious Spectre security flaw in Intel processors. Current mitigations for Spectre variants severely restrain disk-intensive processes such as Adobe Lightroom, Premiere and Photoshop.

In March 2019, Microsoft released cumulative update KB4482887 for Windows 10 October 2018 Update (version 1809) that includes a performance fix called Retpoline.
On my quite old desktop computer with 4th-generation i5 CPU, applying the update and performing the manual actions listed below improved Lightroom performance very noticeably. Microsoft’s own testing shows up to 25% performance increase of disk-intensive programs and apps, and I can back this claim. Lightroom Classic is actually usable again.

Requirements for Retpoline fix

Unfortunately, this fix does not work on all computers. Retpoline requires specific CPU cache behavior that is available on systems with older Intel processors, up to 5th-generation Broadwell: i3-5xxx, i5-5xxx, i7-5xxx and older. You can safely enable the fix on newer systems but expect no performance improvement.

Your device must run Windows 10 October 2018 Update, version 1809: open Settings app (keyboard shortcut Windows Key+I), navigate to System, About and see the version number in the Windows specifications section.

Windows 10, Settings, System, About, Windows specifications

If your computer runs an older version of Windows 10, upgrade to this feature update for free from https://www.microsoft.com/en-us/software-download/windows10.

The KB4482887 update must be applied, use Windows Update for this.

Turning on the Retpoline fix in Windows 10 October 2018 Update

Even after applying the KB44822887 update, you must manually turn on the Retpoline fix. This is because Microsoft still considers it to be in the testing stage.

Open either elevated PowerShell or elevated Command Prompt window: use keyboard shortcut Windows Key+X or right-click or touch and hold the Start button and choose Windows PowerShell (Admin) or Command Prompt (Admin). The availability of either command depends on Start menu settings, but both do the same job.

Windows 10, Quick Links menu, choose ‘Windows PowerShell (Admin)’

Copy the two following commands one by one, use right-click to paste them into the PowerShell or Command Prompt window and press Enter key once to execute the commands:

  • reg add “HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management” /v FeatureSettingsOverride /t REG_DWORD /d 0x400
  • reg add “HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management” /v FeatureSettingsOverrideMask /t REG_DWORD /d 0x400

Restart your device and you’re done! Lightroom, Photoshop, Windows and other programs are faster now.