Function Test-DscNamespace ($ComputerName = $env:COMPUTERNAME) {
    if (Get-CimInstance -ComputerName $ComputerName -Namespace root\Microsoft\Windows -ClassName __NAMESPACE -Filter "name='DesiredStateConfiguration'" -ErrorAction SilentlyContinue) {
         $true
    } else {
         $false
    }
}

$Servers = "Demo-Ad","WC7-1","WS8R2-1","WS8R2-2","WSR2-3-WMF50","WSR2-1"

foreach ($server in $Servers) {
    New-Object -TypeName PSObject -Property @{
        PSComputerName = $Server
        IsPowerShell4 = Test-DscNamespace -ComputerName $Server
    }
}