Apply an Intel XTU profile from PowerShell

tune_ps2.ps1

# Must be run under 32-bit PowerShell as ProfilesApi is x86
[System.Reflection.Assembly]::LoadFrom("C:\Program Files (x86)\Intel\Intel(R) Extreme Tuning Utility\Client\ProfilesApi.dll") | Out-Null

# This script programmatically applies an Intel XTU profile. 
# This script can replace the CLI method outlined here: https://www.reddit.com/r/Surface/comments/3vslko/change_cpu_voltage_offset_with_intel_xtu_on/ 

[ProfilesApi.XtuProfileReturnCode]$applyProfileResult = 0
$profileApi = [ProfilesApi.XtuProfiles]::new()
$profileApi.Initialize() | Out-Null

[ProfilesApi.XtuProfileReturnCode]$result = 0
$profiles = $profileApi.GetProfiles([ref] $result)

$profile = $profiles | Where-Object { $_.ProfileName -eq "Undervolt" } | Select-Object -First 1

if ($profile) {
    $applied = $profileApi.ApplyProfile($profile.ProfileID, [ref]$applyProfileResult)
    if ($applied) {
        Write-Host "$applyProfileResult. Profile applied"
    } else {
        Write-Host "$applyProfileResult. Profile not applied." 
    }
}

sleep 10

The libraries are .NET (managed) assemblies so you can decompile them with ILSpy to see how it works. At least XTU was managed when last used this on 6.5.x.