PowerShell: Optimize RAM on Remote Computers

# simultaneousExec_v0.01.ps1
# Requirement: must run as Administrator

$computerNames="SHERER1","SHERER2"

function installEmptyStandbyList{
    $emptyStandbyListAvailable=(Get-Command EmptyStandbyList.exe -ErrorAction SilentlyContinue);
    if(!($emptyStandbyListAvailable)){
            # Set default protocol to TLS 1.2 and bypass certificate trust issues
            $classTrustAllCerts = @"
                    using System.Net;
                    using System.Security.Cryptography.X509Certificates;
                    public class TrustAllCertsPolicy : ICertificatePolicy {
                        public bool CheckValidationResult(ServicePoint srvPoint, X509Certificate certificate,WebRequest request, int certificateProblem) {
                            return true;
                        }
                    }
"@
            try{
                Add-Type -TypeDefinition $classTrustAllCerts
                $trustAllCertsPolicy=New-Object TrustAllCertsPolicy
                [System.Net.ServicePointManager]::CertificatePolicy = $trustAllCertsPolicy
                }catch{}
            try{
                [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12;
                }catch{
                    [System.Net.ServicePointManager]::SecurityProtocol = [Enum]::ToObject([System.Net.SecurityProtocolType], 3072);
                    }
            $fileName="EmptyStandbyList.zip"  
            $tempDir="C:\Temp";
            $extractionDir="C:\Windows"
            $source = "https://blog.kimconnect.com/wp-content/uploads/2020/02/EmptyStandbyList.zip";
            $destinationFile = "$tempDir\$fileName";        
            New-Item -ItemType Directory -Force -Path $tempDir;
            $webclient = New-Object System.Net.WebClient;
            $WebClient.DownloadFile($source,$destinationFile);
            try{
                Expand-Archive -LiteralPath $destinationFile -DestinationPath $extractionDir;
                }catch{ # Legacy method for backward compatibility
                    $shell = New-Object -ComObject Shell.Application
                    $zipFile = $shell.NameSpace($destinationFile);
                    $destinationFolder = $shell.NameSpace($extractionDir);

                    $copyFlags = 0x00
                    $copyFlags += 0x04 # Hide progress dialogs
                    $copyFlags += 0x10 # Overwrite existing files

                    $destinationFolder.CopyHere($zipFile.Items(), $copyFlags)
                    }
            # copy $destinationFile "$extractionDir\$fileName"
            # Validation
            $emptyStandbyListIsInstalled=(Get-Command EmptyStandbyList.exe -ErrorAction SilentlyContinue);
            if ($emptyStandbyListIsInstalled){
                write-host "EmptyStandbyList.exe has been added into environmental path of $extractionDir successfully."
                }else{
                    write-host "There was an error preventing EmptyStandbyList.exe from being installed onto this system.";
                    break;
                    }
        }else{
            write-host "EmptyStandbyList.exe is already available in this system.`n";
        }	
    }

function optimizeRam{
    (EmptyStandbyList.exe standbylist)+(EmptyStandbyList.exe modifiedpagelist)+(EmptyStandbyList.exe workingsets);
    # Get RAM utilization after 1 minute
    $null=ping -n 60 localhost 2>&1
    $osAndMemory = gwmi -Class win32_operatingsystem -ea stop| select @{Name="computername";Expression={$env:computername}},@{Name="os";Expression={$_.Caption}},@{Name="Memory";Expression={"{0:N2} GB" -f ($_.TotalVisibleMemorySize / 1048576)}},@{Name = "Utilization"; Expression = {"{0:N2} %" -f ((($_.TotalVisibleMemorySize - $_.FreePhysicalMemory)*100)/ $_.TotalVisibleMemorySize) }}
    return $osAndMemory
}

# Limitation: this function currently only takes one function with multiple parameters (that are not nested functions)
function execFunctionAsJob{
    param($computername,$functionName,$parameters)
    #$scriptBlock=${function:$functionName} # another method to retrieve the inside codes of a provided function
    $scriptBlock=(Get-Command $functionName -CommandType Function).Definition;
   
    <# Alternative method
    $session=new-pssession -ComputerName $computername
    $job=invoke-command -Session $session -ScriptBlock{
    param ($importedFunction,$params)
        return [ScriptBlock]::Create($importedFunction).invoke($params);
    } -args $scriptBlock,$parameters
    Remove-PSSession $session
    #>
    $job=invoke-command -ComputerName $computername -ScriptBlock{
        param ($importedFunction,$params)
            return [ScriptBlock]::Create($importedFunction).invoke($params);
        } -args $scriptblock,$parameters -AsJob
    return $job
}

function simultaneousExec{
    param($computerNames,$functionName,$parameters)
    $timer=[System.Diagnostics.Stopwatch]::StartNew();
    $jobIds=@()
    foreach ($computer in $computerNames){
        $job=execFunctionAsJob -computername $computer -functionName $functionName -parameters $parameters
        #$job=execFunctionAsJob -computername $computer -functionName "pingSomething" -parameters "yahoo.com","google.com"
        $jobIds+=,$job.Id
        }
    Wait-Job -Id $jobIds;
    $jobResults=Receive-Job -Id $jobIds;
    Remove-Job -id $jobIds;
    $time=[math]::round($timer.Elapsed.TotalHours,2);
    $timer.Stop();
    $timer.Reset();
    $closingMessage="`r`nOverall Time: $time hours"
    write-host $closingMessage;

    return $jobResults
}

simultaneousExec -computerNames $computerNames -functionName "installEmptyStandbyList"
simultaneousExec -computerNames $computerNames -functionName "optimizeRam"

<# Manual trigger on a localhost: just run these 2 functions
installEmptyStandbyList
optimizeRam
#>