Get-MemoryUsage.ps1

param ([string[]]$Computer = ".")

@($Computer) | % {
    $c = $_
    if ($c -eq '.') { $c = $env:COMPUTERNAME }

    $os = get-wmiobject Win32_OperatingSystem -Computer $_
    $physical = Get-WmiObject CIM_PhysicalMemory -Computer $_

    $free = $os.FreePhysicalMemory
    $total = $os.TotalVisibleMemorySize
    $totalphysical = ($physical) | % { $t = 0 } { $t += $_.Capacity } { $t }

    Write-Host -Foreground 'Cyan' $c
    "Total Physical Memory: {0:N2} GB" -f ($totalphysical / 1GB)
    "Used: {0:p0}" -f ((100 - (100 / $total * $free)) / 100)
    "Free: {0:p0}" -f ((100 / $total * $free) / 100)
    ""
}