Reply To: Query multiple servers for performance counters in parallel

If you have PSRemoting enabled on the target servers, the simplest approach would be to use Invoke-Command. When you pass it an array to the ComputerName parameter, it automatically does the operation in parallel (up to a maximum number at a time, which you can specify with the -ThrottleLimit parameter). For example:

Function Pick-VMHost {

    $Servers = @('host00', 'host01', 'host02', 'host03')
    $UseHost = @{}
    $VMRAM = 1.5GB
    $VMDiskSize = 40GB

    $serverMetrics = Invoke-Command -ComputerName $Servers -ScriptBlock {
        $CPU = (Get-Counter -Counter "\Processor(_Total)\% Processor Time" -SampleInterval 1 -MaxSamples 5).CounterSamples.CookedValue | Measure-Object -Average | Select-Object -ExpandProperty Average
        $RAM = (Get-Counter -Counter "\Memory\Available Bytes" -SampleInterval 1 -MaxSamples 5).CounterSamples.CookedValue | Measure-Object -Average | Select-Object -ExpandProperty Average
        $Disk = Get-WmiObject win32_logicaldisk -Filter "DeviceID='D:'" | Select-Object -ExpandProperty FreeSpace

        New-Object psobject -Property @{
            CPU = $CPU
            RAM = $RAM
            Disk = $Disk
        }
    }

    # Code here locally to determine which host to use from the $serverMetrics array.  Each object will have a PSComputerName property automatically added by PSRemoting.

    $UseHost.PSComputerName

}

$Result = Pick-VMHost