Nvidia and refresh rate

Function Set-ScreenRefreshRate
{
    param (
        [Parameter(Mandatory=$true)]
        [int] $Frequency
    )

    $pinvokeCode = @"       
        using System;
        using System.Runtime.InteropServices;
      
        namespace Display
        {
            [StructLayout(LayoutKind.Sequential)]
            public struct DEVMODE1
            {
                [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
                public string dmDeviceName;
                public short dmSpecVersion;
                public short dmDriverVersion;
                public short dmSize;
                public short dmDriverExtra;
                public int dmFields;
      
                public short dmOrientation;
                public short dmPaperSize;
                public short dmPaperLength;
                public short dmPaperWidth;
      
                public short dmScale;
                public short dmCopies;
                public short dmDefaultSource;
                public short dmPrintQuality;
                public short dmColor;
                public short dmDuplex;
                public short dmYResolution;
                public short dmTTOption;
                public short dmCollate;
                [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
                public string dmFormName;
                public short dmLogPixels;
                public short dmBitsPerPel;
                public int dmPelsWidth;
                public int dmPelsHeight;
      
                public int dmDisplayFlags;
                public int dmDisplayFrequency;
      
                public int dmICMMethod;
                public int dmICMIntent;
                public int dmMediaType;
                public int dmDitherType;
                public int dmReserved1;
                public int dmReserved2;
      
                public int dmPanningWidth;
                public int dmPanningHeight;
            };
      
            class User_32
            {
                [DllImport("user32.dll")]
                public static extern int EnumDisplaySettings(string deviceName, int modeNum, ref DEVMODE1 devMode);
                [DllImport("user32.dll")]
                public static extern int ChangeDisplaySettings(ref DEVMODE1 devMode, int flags);
      
                public const int ENUM_CURRENT_SETTINGS = -1;
                public const int CDS_UPDATEREGISTRY = 0x01;
                public const int CDS_TEST = 0x02;
                public const int DISP_CHANGE_SUCCESSFUL = 0;
                public const int DISP_CHANGE_RESTART = 1;
                public const int DISP_CHANGE_FAILED = -1;
            }
      
            public class PrimaryScreen
            {
                static public string ChangeRefreshRate(int frequency)
                {
                    DEVMODE1 dm = GetDevMode1();
      
                    if (0 != User_32.EnumDisplaySettings(null, User_32.ENUM_CURRENT_SETTINGS, ref dm))
                    {
                        dm.dmDisplayFrequency = frequency;
      
                        int iRet = User_32.ChangeDisplaySettings(ref dm, User_32.CDS_TEST);
      
                        if (iRet == User_32.DISP_CHANGE_FAILED)
                        {
                            return "Unable to process your request. Sorry for this inconvenience.";
                        }
                        else
                        {
                            iRet = User_32.ChangeDisplaySettings(ref dm, User_32.CDS_UPDATEREGISTRY);
                            switch (iRet)
                            {
                                case User_32.DISP_CHANGE_SUCCESSFUL:
                                {
                                    return "Success";
                                }
                                case User_32.DISP_CHANGE_RESTART:
                                {
                                    return "You need to reboot for the change to happen.\n If you feel any problems after rebooting your machine\nThen try to change resolution in Safe Mode.";
                                }
                                default:
                                {
                                    return "Failed to change the resolution";
                                }
                            }
                        }
                    }
                    else
                    {
                        return "Failed to change the resolution.";
                    }
                }
      
                private static DEVMODE1 GetDevMode1()
                {
                    DEVMODE1 dm = new DEVMODE1();
                    dm.dmDeviceName = new String(new char[32]);
                    dm.dmFormName = new String(new char[32]);
                    dm.dmSize = (short)Marshal.SizeOf(dm);
                    return dm;
                }
            }
        }
"@ # don't indend this line

    Add-Type $pinvokeCode -ErrorAction SilentlyContinue

    [Display.PrimaryScreen]::ChangeRefreshRate($frequency)
}

Set-ScreenRefreshRate -Frequency 60
pause